PKACTICAL VENTILATION AS APPLIED TO PUBLIC, DOMESTIC, AND AGKICULTUKAL STKUCTUEES BEING AN ELUCIDATION OF PLANS AND SUGGESTIONS, OP EAST APPLICATION, FOR VENTILATING EVERY SPECIES OF ARCHITECTURAL STRUCTURE WITH KEMAEKS ON HEATING, CONSTRUCTION OF FIREPLACES, CURE OF SMOKY CHIMNEYS } AND AN APPENDIX ON THE VENTILATION OF SHIPS, STEAMBOATS, AND RAILWAY CARRIAGES KOBEKT SCOTT BUKN WILLIAM BLACKWOOD AND SONS EDINBURGH AND LONDON MDCCCL PRINTED BY WILLIAM BLACKWOOD AND SONS, EDINBURGH. CONTENTS Page Agricultural structures, ventilation of, - 87 Air, amount of, required per minute, - -11,40 causes of deteriorated, - 15 supply of, - 25 source of, for ventilation, - - 26 fresh, ventiducts, - - ib. foul, - 35 extraction of foul, 30 supply of galleries, channel for chimneys, - - - - 166 Amount of air for stables, - 92 Apartments, fresh-air ventiducts for private, - 63 Apertures, rules for ascertaining area of, * Arnott's room ventilator, - 68 stove, - - 117 Artificial ventilation, - - 18 Attendants, rules for the guidance of, - 60 Bed-rooms, - 82 Boilers, construction of, - - 126 Bryden's ventilator for apartments, - '-- ' - 176 Bude light, - 54 Carbonic acid gas, 5 Chimneys, size of, - 1 52 flues, diameter of, - - 159 smoky, - 158 top, - 40, 169-171 Chowne's, Dr, ventilator, ... - 55 iv CONTENTS. Page Churches, ventilation of, - 46,182 section and plan of, 46 Churchwardens, - 144 Circular fresh-air valves, 50 Construction of boilers, - - 126 fireplaces, - - - 145 Conduction of heat, - 113 Coved or sloping roof, - Coaches, railway, ventilation of, - 201 heating of, - 205-206 private, ventilation of, - - 207 Deflecting chimney-top, - 169 Dairies, ventilation of, - - 110 Damper valve, - - 29 door for furnaces, - - 1 31 Damage by fire, prevention of, - - 1 56 Distribution of heating pipes, - 136 Draughts, 83 Drying-houses for grain, 95 process in, - - ib. area of ventiducts for, - - 97 valves, mode of working, - 98 section and plan of, - 100-101 rules for finding surface of heating-pipe for, - 1 02 for seed, peat, &c., - 104 temporary, - 105 Emigrant ships, ventilation of, - - 193 Engine-rooms of steamboats, - - 197 Expansion of pipes for heating, 132 Extraction of foul air, - 30 Fanners, working of, - - - 199 Feed-apparatus for boilers, - - 127 Fever, typhus - 7 Foul air, effects of, - 6 ventiducts, 35 valves, - ' - - - - ib. withdrawal of, from apartments, - - 68-73 Fresh-air ventiducts, - 26 valves, - 28 for apartments, - 63 Furnaces, - 129 area of chimney for, - - 130 Galley fire, ventilation by, - - - - 192 CONTENTS. v Page Galleries, supply of air to, - - 38 Gaslights, - 75,178 Guager's chimney-top, - - 170-171 Gauge-cocks, - - 129 Grate-bars, - - 146 Grates, combustion in, - - 147 Heat, radiation of, - - 112 conduction of, - - 113 Heating apartments, - - 138 churches, - - - 137 portable apparatus, - 1 04 by steam, - - 120 by hot water, - - 121 Hospitals, 46 Hosking's, Professor, ventilating grate, 81 Houses of Parliament, - 54 for drying grain, &c., - 95 Index for valves, 37 Lights, tubes for gas, - - 178 - -, shop window gas, 79 Lungs, surface of, - - 2 Management of lights, 53 Medicator air for ships, - 196 Mode of drying seed, turf, &c. - - - 104 of contracting chimney top, - - - 168 of working fresh and foul air valves in concert, - 98 of supplying air to cabins, - 188 of supplying heat to railway coaches, - - 205-206 of preventing birds from building in ventiducts, 48 Natural ventilation, - 17 Nature of ventilation, - 1 9 Ornamental scroll-work for ventilators, 74 Paddles, ventilation by, - 197 Peat, mode of drying, - - - 105 Pedestals, ventilating, for ships, - 188 Perspiration, weight of, 5 Plan of Church, 46 of drying-house, - - 101 Pipes, heating, - 131 , distribution of, - - 134 Porcelain stove, - 118 Portable heating apparatus, - - - 107 Private apartments, - 63 vi CONTENTS. Page Process of drying, - 95 Process of respiration, 1 Proportions of pipes for heating, - - 134 Pulpits, ventilation of, 45 Radiation of heat, - 112 Railway Carriages, - - 201 , ventilating pedestal for, - - 202 , heating of, - 205-206 Recapitulatory remarks, -: 173 Respiration, process of, 1 Roofs, flat and coved, - 32 Rules for ascertaining the area of ventiducts, - 39 for ascertaining the area of ventiducts for drying-houses, 97 for ascertaining the surface of heating pipe, - 1 02, 1 34 for the guidance of attendants, - 60 Samaritan fund, 23 Scrofula, 8 Section of church, . - 46 of drying-house, - - 100 Shop window-lights, - 79 Skylights, mode of ventilating by, - 66 Sleeping berths in ships, 184 Source of air for ventilation, - 26 Stables, arrangement of, - 88-91 , ventilation of, - 91 , amount of air required for, - 92 Steam, heating, - 120 boilers, construction of, - " 126 Steamboats, ventilation of, by funnel, - - - 198 furnaces, - ib. ventilating by engine power, - 199 Stoves, heating by, - .116 , Arnott's, - 117 , Porcelain, . 118 Study, heating of, - 139 Supply of air to galleries, - 38 Swine cots, - 110 Temporary drying-house, - -105 Tin ventiduct for windows, - - - .. 64 Theatres, 52 Top for ventiducts, - 41 Tops for chimneys, - - 170-171 Tubes for gas lights, - - - - - 178 CONTENTS. vii Page Valves for foul air ventiducts, 35 for fresh air ventiducts, - - - 26 circular, - - - 50 Ventiducts, fresh air, - - - - 26 , foul air, - - - 35 Ventilation, nature of, - - - . 17 , natural, - .... 39 , artificial, . . 13 of gas lights, - - - 75 of private carriages, - 207-208 Ventilating tube for apartments, - 73, 174 tubes for gas lights, - 178 pedestals for ships, . 188 steamboats by fanners, - - - 199 by screw, - . . 200 by paddles, . . 197 by galley fire - - - 192 by engine power, - 199 lamps for railway carriages, - - 204 Ventilator, Arnott's, for apartments, - 68 funnel, - - - 176 syphon, - 55 zinc, for apartments, - 64 Warming grate, ... 140 Windsail ventilator, - - 1 89 Workshops, ventilation of, - 80, 182 Zinc ventilator, 64 APPENDIX, - - - . . - 185 INTRODUCTION THOUGH many years have elapsed since men of science first demonstrated the fact that the inhalation of impure air, which had been previ- ously expelled from the lungs, exerted a very deleterious effect upon the party subject to its influence; still it has been only within a very short period that the importance of Ventilation, not only as a means of withdrawing foul from, but of securing a large supply of fresh air to, the interiors of our houses, has been fully recognised : and its due value assigned to the fact that such supply is eminently conducive to the right per- formance of the mental, as well as of the physical functions of the human frame. For a considerable period, however, after the necessity of Ventilation had become fully established, it was considered more as a subject interesting in the study, than as a means of actually removing the evils which x INTRODUCTION. it proposed to obviate : in fact, it was more treated of theoretically, than attempted to be reduced to practice. By the appalling disclosures given in the admirable Keports of the Parliamentary Commis- sioners, appointed to examine into what in the popu- lar language of the day is known as the " sanitary condition 1 ' of our large towns and by the efforts of private individuals, the attention of the public has been at last forcibly arrested to the subject. Thus, as in all similar cases, practically scientific men were encouraged to give their attention to the subject : plans were proposed, and in some cases carried into effect ; and the Legislature by its exertions gave a mighty impetus to the movement. Experience gave rise to many improvements; some of our first men of science promulgated their ideas on the subject ; philanthropists began to interest themselves in the improvement of. the dwelling-houses of the poor ; the art was more and more divested of its intri- cacy and apparent difficulty ; the simple laws of nature regulating the motions of the atmosphere were taken advantage of, and rendered subservient to simple modes: and the result of all this has been the establishing of the fact, that not only is the ventilation of every structure which man inhabits and uses practicable, but that it can in every case be effected easily and cheaply. INTRODUCTION. xi The Author of this Treatise has for many years devoted his attention almost exclusively to the subject of Ventilation, and has studied, with a view to their introduction, the various plans promulgated during the last few years. Convinced of the great importance of the subject, and being of opinion that a Work is much wanted at the present time, in which it is presented in an available point of view, elucidating it in simple explanations free from technicalities he has been induced to prepare the following Remarks for publication. In throwing together the results of his own experience, and in explaining the methods of others, he has endea- voured to give those only which can be termed " eminently practical ;" invariably preferring to give such, rather than theoretical details not neces- sary for the understanding of the system: his object being to present a Work which can be referred to for useful purposes, and which, by simplicity of arrangement, can be rendered easily available. In bringing his ideas before the public, he has adopted an arrangement, of which the following is a synopsis or general view. In the First Chapter are given a few brief remarks on the necessity for, and the importance of, Ventilation ; with a sum- mary of the evil effects produced upon the system xii INTRODUCTION. by the body being subjected to the influence of " impure air." The Second Chapter is occupied with an explanation of the nature and principles of Ventilation, and of the most thoroughly practical plans for ventilating public buildings, illustrated with the necessary diagrams, with ample descrip- tions and suggestions. Chapter Third is devoted to the consideration of methods for securing a good supply of pure air to the interior of domestic structures ; described in simple terms, yet with sufficient fulness to enable any one to carry them into effect. The Fourth Chapter contains descrip- tions of methods adapted especially to agricultural edifices. The Fifth Chapter is on Heating a kindred subject, and one of great importance in domestic arrangements, and in the arts ; and which, more- over, when a good system is adopted, is a great assistant to efficient ventilation. In this depart- ment the principle of giving only practical remarks is rigidly adhered to : such, it is hoped, will be found to be of eminent service, and easily carried into effect. The construction of fire- places, with a view to the economisation of fuel, and the prevention of smoke, is considered. And, with a few general Eecapitulatory Kemarks, the subject is closed. INTEODUCTION. xiii Though somewhat foreign to the nature of the Work, an Appendix has been added. In this are given some remarks and suggestions, possessing some small degree of novelty, and capable of being applied to the ventilation of Ships, Steamboats, and Kailway Carriages. The whole is illustrated with Woodcuts, by which the descriptive text is made familiar, and the suggestions rendered easily available by he architect, the builder, and the agriculturist. March 25, 1850. PRACTICAL VENTILATION CHAPTEE I. THE NECESSITY AND IMPORTANCE OF VENTILATION. " It is not air That from a thousand lungs reeks back to thine, Sated with exhalations rank and fell ; " ' It is not air, but floats a nauseous mass." " Immersed in many a sullen bay, That never felt the freshness of the breeze, This slumbering deep remains, and ranker grows With sickly rest." ARMSTRONG'S Art of Preserving Health. AMONG the natural agents necessary for the support and enjoyment of existence, with which a beneficent Creator has supplied us, the atmo- sphere by which we are surrounded performs an important part. Viewed as the medium of con- veying, with equal facility, the rays of light, the vibrations of sound, the fragrances emitted from the shrubs and flowers of the teeming earth, and the gentle exhalations which, ascending to the A 2 THE NECESSITY AND clouds, form the aerial reservoirs from which the parched lands are supplied with grateful moisture, it presents to the inquiring mind a subject as inte- resting, in its general features, as beautiful in the precision of the laws which regulate its motions. But with reference to its influence upon the func- tions of the human frame, it presents another phase equally important and interesting. " It forms," says an eloquent writer, " the great pabu- lum vitcBj to which all other nourishment is sub- ordinate, and without which death immediately ensues. Not only does it act constantly, wherever it presses upon the surface of the body it is even brought into contact with the blood, within the inmost recesses of the lungs, where its renovating action purifies this vital fluid before it returns to the heart, from which it circulates in a living stream to every part of the body, producing a never-ceasing circle of chemical changes, so long as there is life to sustain its movements. Nor has nature been more profuse in its supply of that aerial fluid with which we are surrounded, than careful in the means adopted for its efficient appli- cation." What these are we will now see, in describing the rationale of the process of respira- tion, and the action of the air on the blood. The windpipe, passing into the chest, is divided into two branches, one going to the right, the other to the left lung. On entering the lungs, the branches IMPORTANCE OF VENTILATION. 3 are divided into innumerable little tubes, terminat- ing in minute globular cells, all of which commu- nicate with one another: the number of these is very great, the surface presented by the mass being computed, according to some, to be as much as 1500 square feet. Dr Reid, however, gives it as his opinion, that 400 square feet may safely be taken, as pretty near the truth. By the muscular action of the upper part of the body, the air is drawn down the windpipe through its innumerable branches, and the connected cells of the lungs, where it acts upon the blood, which likewise circu- lates through them. The two great canals, if we may use the expression, by which the blood is conveyed in its various courses, are the veins and arteries the former conveying the blood to the lungs to be purified, the latter conveying the pure blood to the various parts of the body, giving off, in its course, " warmth, strength, and life.' 1 The colour of the blood in the veins is of a dark purple tint ; in the arteries it is a bright red. If we could see the internal mechanism of our bodies in opera- tion, we would perceive the veins pouring in the dark impure blood to one side of the heart, from thence forced to the lungs, there receiving the oxygen of the air contained in the cells ; thereafter sent to the other side of the heart, from which it would be led off through the arteries a bright red colour. The air used in respiration, (drawn in, 4 THE NECESSITY AND as we have seen, to the lungs,) is supposed, accord- ing to the generally received opinion, to impart its oxygen at once to the blood the blood, in its course through the body, receiving various impu- rities, of which the principal is carbonic acid gas these products .being expelled principally by the elasticity of the lungs, assisted by muscular action of the body. Such, then, divested of all unneces- sary elaboration, is a simple explanation of the rationale of respiration, and the action of the air upon the blood. The object of this process, (only suspended when death ensues,) which has been termed " the ventilation of the lungs," is to remove the " vitiated, which is exhaled into the lungs, and to supply a corresponding quantity of fresh air." Seeing, then, that the purification of the blood, which is the life-supporting fluid, depends upon its receiving a due supply of oxygen, it is evident that this purpose cannot be served by inhaling air previously deprived of that necessary component. It is of little use sending the blood to the lungs in which there is already bad air ; such must result in deteriorated health. But it is not only through the lungs that pure air exerts a beneficial influence upon the body, or vice versa .- the skin, pierced by its numerous pores, also exercises a function of considerable importance. Through its minute tubes, the air exerts an influ- ence upon the blood similar to that which is per- IMPORTANCE OF VENTILATION. 5 formed, though with unremitting energy, by the lungs. From many controlling circumstances, these do not act with the same precision ; but in a healthy person the inhalation of pure, and the exhalation of impure air, through the medium of the skin, goes on with considerable regularity. Lavoisier estimated that a man gives off, by insen- sible perspiration, fifteen grains of vapour per minute ; and it has been ascertained that pure air, by being in contact with the skin, becomes chiefly carbonic acid gas. A large supply of pure air, then, is as necessary for the due performance of the functions of the human body, as nourishing and wholesome food. This is evident, when we consider the process in continual operation in the living subject. We have stated that carbonic acid gas is the chief product of respiration : now, from the deadly na- ture of this gas, it must exercise, when inhaled into the lungs, a very deleterious influence upon the constitution. In its pure state it extinguishes flame, and kills almost instantaneously living objects presented to its influence. When more diffused, its effects are not so observable; nevertheless, they are u slowly and insidiously produced, and thus too generally overlooked, until the constitution is generally impaired, and the body equally en- feebled." " Independent," says the able writer from whom we have already quoted, " of the more 6 THE NECESSITY AND serious evils, there are various minor evils, that often prey upon the constitution when the air is of inferior quality : the long-continued action of the vitiated air gradually undermines the tone and strength of the stomach ; the appetite diminishes, and the citadel or mainspring of the constitution being thus disabled or destroyed, all the other powers of the system, also, gradually give way. Premature old age is, indeed, one of the most cer- tain consequences of long exposure to a vitiated atmosphere ; and in various occupations, the short span of human life is abridged many years by this cause, independently of the low tone at which it often flows, and the endless discomfort and annoy- ance to which, in such cases, it is often subjected. Nor are the moral and intellectual faculties to be forgotten, in considering the influence of a vitiated atmosphere. The energy and tone of both is lowered and depressed by bad air : these are impaired at least as much as the corporeal functions, and, when not subdued by the mere force of the oppression to which they are subjected, are often forced into an unnatural state of excitement, wholly incompatible with health, and with the sober exercise of the reasoning faculties." The startling disclosures made within these few- years, have abundantly proved the fact, that to defec- tive ventilation may be attributed the widespread existence of more serious evils we allude to typhus IMPORTANCE OF VENTILATION. 7 and other malignant and pestilential fevers. It has been computed that " the animal slaughter, in Eng- land and Wales, from prevcntible causes of typhus fever, which attacks persons in the vigour of life, is double the amount of what was suffered by the Allied armies at the battle of Waterloo." We believe this is no exaggeration. In Great Britain, there is every year a "battle of life" fought ; the victims being the inhabitants of our towns the victors, the deadly typhus and pestilence. " However appalling," says Dr South wood Smith, " the picture presented to the mind by this statement, it maybe justly regarded as a literal expression of the truth. I am myself con- vinced, from what I constantly see of the ravages of this disease, (typhus,) that this mode of putting the result does not give an exaggerated expression of it. Indeed, the most appalling expression of it would be the mere cold statement of it in figures." In addition, however, to the influence of impure air in generating disease, it materially contributes to its propagation. A certain degree of concentra- tion generally appears to be necessary for, and in- variably predisposes to, the occurrence of an attack of fever. In confirmation of this, we adduce the following evidence of Dr Arnott's : " In a public building at Edinburgh, when the number of cases of fever began to exceed a certain proportion of all the cases of disease in a ward, the fever began to affect the nurses, who were constantly present, and 8 THE NECESSITY AND therefore much exposed to the infection ; when the proportion became still greater, it affected also the students, who were less exposed to it than the nurses, but more than the physicians ; and, when increasing still further, it affected also the physi- cians." This was when the wards were occupied chiefly with fever patients. " But when such pa- tients were scattered about, so as to dilute the poison, the attendants remained safe, as did also the neighbouring patients in the beds about them : thus proving that dilution of the contagious poison, by scattering the patients, as well as the complete ventilation of a fever ward, affords safety." But fever is not the only disease rendered more extensive in its ravages by defective ventilation : such is " but a drop of water in the ocean, compared with the other less obtrusive but more dangerous maladies that silently disorganise the vital structure of the human fabric, under the influence of this deleterious and invisible poison." The most im- portant of these are, consumption and scrofula. With reference to the first, Dr Guy states that almost all cases amongst the working classes are occasioned by confinement in over-heated workshops, at seden- tary occupations ; but its ravages extend to all classes, the rich and wealthy suffer likewise. It is in connexion, however, with scrofulous diseases that the evils of impure air are so strikingly obser- vable. Joseph Toynbee, Esq., a gentleman who IMPORTANCE OF VENTILATION. lias devoted much of his time to the consideration of the subject, gives the following evidence, sup- ported by that of a celebrated French physician : " Defective ventilation appears to me to be the principal cause of the scrofulous affections which abound to an enormous extent amongst our patients. When I have had a scrofulous patient come before me, I have always been able to trace this as one of the agents. When it is seen, on the other hand, that this disease never attacks persons who pass their lives in the open air, and manifests itself always when they abide in an air which is unrenewed and this, whatever may be the extent of other causes it appears evident that the non- renewal of the air is a necessary condition in the production of scrofula. Invariably it will be found, on examination, that a truly scrofulous disease is caused by a vitiated air ; and it is not always neces- sary that there should have been a prolonged stay in such an atmosphere often a few hours each day is sufficient. And it is thus that persons may live in the most healthy country, pass the greater part of t!he day in the open air, and yet become scrofulous, because of sleeping in a confined place, where the air has not been renewed." An example of the truth of these statements maybe given: " At three leagues from Amiens lies the village Oresmeaux. It is situated in a vast plain, open on every side, and elevated more than 100 feet above the neigh- 10 THE NECESSITY AND bouring valleys. About sixty years ago, most of the houses were built of clay, and had no windows ; they were lighted by one or two panes of glass fixed in the wall; none of the floors, sometimes many feet below the level of the road, were paved. The ceilings were low the greater part of the in- habitants were engaged in weaving. A few holes in the wall, and which were closed at will by means of a plank, scarcely permitted air and light to penetrate into the workshop. Humidity was thought neces- sary to keep the threads fresh. Nearly all the inhabitants were seized with scrofula ;, and many families, continually ravaged by that malady, be- came extinct; their last members, as they write me, died rotten of scrofula. A fire destroyed nearly a third of the village ; the houses were rebuilt in a more salubrious manner, and by degrees scrofula be- came less common, and disappeared from that part." We could fill a volume with facts illustrative of the baneful effects of vitiated air on the health of the human frame ; but we have, we opine, cited enough. When it has been affirmed that " non-ventilation is a more fatal cause of disease than any other" when, in addition to those already noticed, it is shown to be productive of many minor evils as cattarh, rheumatism, disordered digestion, nervous complaints diseases- of the joints, of the skin, of the delicate organs of the eye and ear and, to sum up the dreary list, a " predisposing and aggra- IMPORTANCE OF VENTILATION. 11 vating cause of every species of bodily affliction to which mankind are subject," surely the reader will be convinced of the great necessity existing for efficient ventilation, securing everywhere to the habitations of man a large supply of pure air. If the beautiful process of respiration has been ordained and set in motion within our " earthly tabernacle " for the purpose of freeing it from im- purities which would cause disease and pain if allow- ed to remain ; is it not worse than folly to act in our daily lives counter to this plan, and, refusing the pure air given us, perversely choose that which, impure and deteriorated, only induces disease ? And yet this is done every day. In the great ma- jority of houses, no provision whatever is made for the admission of fresh air. It has been calculated that no less than 400 cubic inches of air is required by each individual per minute ; yet actual obser- vation has proved that, " in an immense majority of houses in different towns, the quantity of fresh air admitted did not amount to more than one fourth of the minimum required." While studying the subject of atmospheric influence upon the body, nothing strikes the inquirer more forcibly, on be- coming alive to its importance, as the indifference with which a supply of pure air to the lungs is considered by the great majority of people. Could a person, ignorant of the process, see vividly pre- sented to his mind the poisonous action of impure 12 THE NECESSITY AND air upon the blood, we feel convinced that he would be startled by the contemplation of the facts presented to his notice. He would, in very truth, see that he might, with as*much certainty of ultimate punishment, mix diluted active poisons with his meals, as breathe air deteriorated in its quality. This is no exaggerated mode of putting the matter ; it is sober truth, too often, alas, proved by the pale- faced, the emaciated, and diseased around us. It is amazing with what indifference people look upon the existence of impure air in their dwellings. Pre- senting nothing tangible or visible, so long as its influence does not result in marked or immediate effects, they are content to abide its presence. Many who pride themselves on their fastidious taste, in other objects necessary for the support of life, will, with a freedom as astonishing, as it is melancholy in its results, breathe air most foul and impure in its quality. It is, however, gratifying to the philan- thropic mind, to find the ignorance existing on this important subject becoming gradually dispelled ; that the veil so long hiding the real merits of the question is fast being removed ; the evils of the old system becoming daily more understood and dreaded, and a desire for a better order of things more manifested. On the other hand, comparatively little practical advantage has been taken of the know- ledge so extensively enjoyed; " the rough and rude treatment to which the lungs are subjected, the IMPORTANCE OF VENTILATION. 13 vitiated atmosphere which they are so often called to inhale, and the transitions of atmospheric and artificial temperatures to which they are carelessly subjected, show clearly how little the value of a mild and fresh atmosphere is practically appreciated; while the ravages of consumption, and the ex- tended catalogue of evils accompanying diseases of the organs of respiration, point out the vast amount of misery that might be obviated, and of death that might be prevented, were the leading principles and practice of ventilation more generally understood." With the expression of the hope, that practical knowledge will become more and more extended and made use of in daily life, we close this part of our subject by quoting the words of Dr South- wood Smith a gentleman to whom our country owes much, for his philanthropic exertions in connexion with the amelioration of the condition of the poorer classes of society : " Nor is there one, among the many questions thus forced upon the attention of every civilised community, which is itself so important, or the correct solution of which is so indispensable to the preservation of health, as the investigation of the best and simplest means for providing, in every space occupied by human beings, a gradual but constant change of air. Innumerable are the catastrophes, some of sufficient magnitude to occupy the page of history, which testify to the necessity for man carrying out, in his 14 IMPOKTANCE OF VENTILATION. dwelling, the same principle upon which nature has proceeded in the fabrication and endowment of his body. She has, by a simple and efficacious process, provided for the ventilation of his lungs ; and it is for him, using the, reason with which he is blessed, and imitating the beneficent provisions indicated by science, to direct through every place which he inhabits a gentle current of that invisible atmosphere, which was intended to be the source of life, but which has hitherto been too frequently a transmitter of disease and death" CHAPTER II. VENTILATION OF PUBLIC BUILDINGS. ' The trembling air that floats from hill to hill From vale to mountain, with incessant change Of purest element." ARMSTRONG. BEFORE entering into the explanations of practical details, we deem it necessary to review shortly the causes of the existence of vitiated air in the interior of public buildings ; and to explain the rationale of the process of ventilation. Air is principally dete- riorated by the evolution of carbonic acid gas from the lungs, one of the chief productions of respi- ration. This gas, as we have before mentioned, cannot support life or combustion ; it possesses such a deleterious influence, that, even, when placed in contact with the exterior surface of the skin, it inflames and reddens it. " In general, when any attempt is made to inspire pure carbonic acid gas, a convulsive movement induced at the entrance to the windpipe closes the aperture, and prevents ingress. In some cases, there is reason to believe 16 VENTILATION OP that the movement has not been sufficient to exclude the carbonic acid, and immediate death has ensued. It is not known that there is any hope of recovery where carbonic acid freely enters the lungs. Death has ensued, in some particular cases, where there was only one per cent of the gas present. Any ordinary atmosphere containing one per cent of carbonic acid must be regarded as of very inferior quality, and not fit to sustain health, though, in numerous apartments, a much more vitiated air may be observed. The lower the tone and strength of the constitution, the more alive does it become to the depressing influence of air contaminated with carbonic acid. The old and the infirm sometimes sink in an atmosphere of which the robust and vigorous may take no notice. When the quantity of carbonic acid is reduced to a proportion varying from the one-thousandth and two-thousandth part, it does not produce deleterious results. Common air contains a minute proportion of the gas, even at the highest altitude at which it has been examined. Carbonic acid gas being the principal impurity communicated to air in all ordinary apartments, the amount present may in general be taken as an index of the state of the atmosphere and of the effi- ciency of any ventilating arrangements." A simple mode of testing may be adopted : a perfect analysis is not required. Lime water, placed in an open dish, will show the presence of the gas. Air is also PUBLIC BUILDINGS. 17 deteriorated by the volatile products emanating from the pores of the skin. The mode of lighting also tends to the same result : the flame of a gas jet, equal in brilliancy to a common candle, renders from 200 to 300 inches of air per minute unfit for respiration. The mechanical impurities found in buildings, as dust, &c., also to a certain extent vitiate the air used. Having thus reviewed, very briefly, the causes of the existence of vitiated air in public buildings, we will now proceed to explain the pro- cess of ventilation. Air, when expelled from the lungs after being used for the purposes of respiration, being composed principally of a heavy gas, it has been argued that the specific gravity is such that it has a down- ward tendency. Now, although carbonic acid gas is more than one-half heavier than water, still, in its passage through the lungs, it acquires as much heat as to give it an upward tendency of very consider- able force. This may be very familiarly illustrated, by breathing in the open air on a calm day in frosty weather : the breath will be seen floating upwards. This may be rendered more convincing : by blowing the breath forcibly downwards, the same result will be obtained. That this law has been ordained for benevolent purposes we cannot for a moment doubt ; the mixture of vitiated air is found to be much lighter than that of common pure air at the same temperature. In this arrange- B 18 VENTILATION OF raent we have to admire another of the simple, yet beneficent laws, appointed to minister to our com- fort. Air, when vitiated, having thus a high tem- perature imparted to it, rises, when allowed to escape, with such velocity, as soon to be borne away above the zone of respiration, so that, in such cases, it cannot be breathed again. It is for man, then, to take advantage of this simple law, and, by allowing free egress to the vitiated air, supported by other modifications, to free himself of this active agent in producing disease. Ventilation may be divided into two classes artificial and natural. By artificial, currents of air may be exerted in any direction upwards, down- wards, or laterally ; this being effected by machines and contrivances, as pumps, fanners, screws, and we may here specify fire-draught. Artificial ven- tilation is divided into two branches, " plenum " and "vacuum." Plenum ventilation may be briefly described as the mode where air is forced into the interior of a building, the vitiated air being allowed to pass out by the channels made for that purpose, or by the crevices of the doors, windows, &c. "The certainty of introducing," says Dr Keid, " without mixture, the air that is considered best, forms the great peculiarity of plenum ventilation, which can be sustained only by the constant use of machinery." The vacuum impulse is sus- tained by machinery, which pumps or extracts the PUBLIC BUILDINGS. 19 air from the interior allowing the fresh air to enter by the crevices of the doors, or by apertures pro- vided for that purpose. Natural ventilation does not, however, depend upon machinery for its results, but is " a process by which movements are induced or sustained in the air, in the same manner as wind is produced in the external atmosphere." The rationale of natural ventilation cannot be better described than in the words of Dr Reid : " The specific gravity of air vitiated by respiration and combustion, the two great processes that deteriorate air in ordinary buildings, is under ordinary circumstances less than that of common air: it gives way accordingly, and is pressed upwards by the denser and purer air. Let us imagine, then, an apartment occupied by a number of persons standing on a porous floor, and the roof taken off: at ordinary temperatures, the air, vitiated there by the human frame, requires no mechanical power to remove it. The superincum- bent pressure is diminished by the expansion induced in the air as it is heated; but the external air is permitted to have free access below, as well as above, to the porous floor. Its power therefore preponderates, and an upward movement is the necessary consequence ; which is accompanied by the introduction of fresh air and the removal of that which is vitiated. Here, then, is a species of natural ventilation. All that is essential is merely 20 VENTILATION OF this, that the natural movements induced by the heat of the body shall not be stopped by any barrier opposed to them. An open roof and ceiling is, how- ever, inadmissible : protection is required from the weather, independent of other arrangements. The opening, accordingly, may be contracted : in pro- portion to the amount of contraction, the tempera- ture of the air, and the numbers on a given space, it now becomes necessary to increase the velocity of the discharge from the apartment referred to. To effect this, if a shaft or chimney be extended from any opening in or near the ceiling, the column of warm air which soon fills it increases its power ; and unless an extreme number of individuals be crowded in the apartment, the shaft is sufficient for all ordinary purposes. It acts at all times, if the air within is less than the density of the air without ; and, when this is not the case, its power can still be developed by kindling a lamp or fire, or merely by increasing the temperature of the apartment for which it is applied as any of these causes produces the necessary diminution of densitv or rarefaction within, on which its force depends." Such is an admirable explanation of natural ventilation. In all cases where the nature of the building will admit of it, natural ventilation should be adopted, and the simple laws which regulate its motions taken advantage of. We venture to say, that nine buildings out of ten can be efficiently ventilated PUBLIC BUILDINGS. 21 without the aid of any machinery whatever. A writer on the subject, in passing severe strictures on builders, in endeavouring as much as possible to close up every aperture by which air can gain ad- mittance to dwelling-houses, says, " that luckily, in spite of all their endeavours, their close-fitting doors and windows, air still finds access.' 1 And so it is : the laws founded for a benevolent purpose will act, however much man may retard and oppose them. Is it not consistent, then, with natural laws, to suppose that if air/orces itself into apartments, when every means are taken to exclude, and, when once in, to confine it ; that surely it will gain easier admittance when apertures are formed to facilitate its admittance, and, when deteriorated, to allow it likewise to escape ? And yet many strenu- ously advocate the use of machinery, more or less complex, in almost all cases, when ventilation is required ; as if it were an absolute impossibility to supply air to their interior without such mechanical appliances. The writer whose definition of natural ventilation we have given, says, that the ascent of air in shafts, at the ceiling, acts in all cases where the density of the air within is less than that of the air without. Now this opinion is that of one who has had more experience in practical ventilation than any other we are aware of, and it is amply corroborated by the result of every day's experience. The cases will be very rare indeed, where the condi- 22 VENTILATION OF tions requisite, as implied in the above, will not be fulfilled. In winter, the heated air in the interior is sure to be of less specific gravity than the cold air on the exterior; and even in summer, although the heat of the breath in the interior, and that of the air in the exterior of the building, may be nearer in equality than in colder weather, there is, and must be, a decided difference in favour of that in the interior. This is amply proved when the fact is considered, that it is much hotter in a crowded building than in the open air, however calm, in a hot summer-day: the heat of the bodies, in a certain degree raised in temperature, in proportion to the number of people assembled, and the concentration of the heat by the confinement, all tend to the result found. Not only can buildings be ventilated efficiently, by the adoption of the laws in constant action, but, what is of considerable importance, the expense of doing so is comparatively trifling ; moreover, when once effected, repairs are not required, or the expenditure of any expensive power to maintain its operations, necessary. Again, there are no complicated arrangements, difficult to be understood by that class who, in all public buildings, will generally be found to have their management. But, apart from these considera- tions, we would advocate the adoption of the simple plan on grounds of policy. So long as the PUBLIC BUILDINGS. 23 public opinion, too generally current, is believed, that ventilation is an exceedingly complicated science an important one, doubtless, yet requir- ing erudite knowledge to apply its principles prac- tically, and in the adoption of which great expense is incurred, and complicated machinery requisite so long will the apathy generally existing on this important subject continue. It is exceedingly difficult to persuade people to lay out money for the prevention of evils of which they are not too well convinced, and which are invariably attri- buted to other causes. Moreover, if the idea is once obtained, that the operation of ventilation is very expensive, however much they may be alive to its importance, the very dread of the expendi- ture suffices to allay their fears, or is at least pro- ductive of the effect evidenced by the saying " Oh ! there is no use at all in thinking about it, it is so expensive." Let, however, the fact be generally understood, that ventilation is within the reach of almost the very poorest mechanic in the land, and a new spirit of inquiry will soon be abroad. By the numerous cheap publications which find their way into every housej people heretofore ignorant are becoming aware of the importance of the subject ; and if they are like- wise made aware of the cheapness and facility of construction of useful plans, a demand will soon arise for such. We have had ample proof of the 24 VENTILATION OF truth of this in the experience of the Samaritan Fund, established in London, for supplying the habitations of the poorer classes with "ventila- tors : " the demand made by poor people is every day increasing, and there is reason to believe that it will continue to do so. Let those who are anxious to promote the introduction of plans, endeavour to promulgate as much as possible those more remarkable for their simplicity than com- plexity. We do not say that we can obtain, with- out machinery, those complicated movements of air, which can be moved or drawn with precision in any direction ; but such are not required. Let a desire for thoroughly efficient plans be introduced gradually; let the benefits of a supply of air, though not so nicely controllable in its motions, be appreciated, and we have no fear that, in process of time, a demand for more complicated plans will be created. In no important movement is success all at once obtained ; the old proverb, " Little by little," is a good one, and from which something may be learned. Let all endeavours to divest the subject of apparent difficulties be strenuously made : by the introduction of simple plans, curi- osity will be excited, inquiries will be made ; and that indifference, too justly complained of, which is now existing, will be done away with, and the adoption more generally of efficient modes be the decided result. PUBLIC BUILDINGS. 25 Having, then, avowed a preference for the plan of ventilation which (by availing ourselves of na- tural laws, simple and unvarying in their action) can be easily and cheaply adopted, we will now proceed to the more immediate consideration of our subject. In ventilating buildings, two things should be borne in mind; and as upon the proper attention to these depends the success of the plan, particular attention should be taken to see them carried into effect. These are, the supply of the interior with fresh air, and the withdrawing of it when vitiated. And here we would request attention to the fact, of which the evidence of all experience goes to prove the truth that no foul air can by any possibility be extracted from the interior of any building, hoioever well arranged the means to insure its exit may be, un- less an ample supply of pure air is admitted. " A moment's reflection will satisfy the mere student as to the truth of this position. ... It is the force of air entering that causes the vitiated air to be expelled. It is necessarily impossible to have ventilation without a movement of air. At all times a tendency to movements in the air, or the production of a draught or current may be oberved, proportional to any inequalities of temperature that may arise from natural or other causes, or the action of any mechanical force." In making pro- visions for the supply of pure air, due regard should be had to the source from which it is sup- 26 VENTILATION OF plied. If much dust or extraneous mechanical im- purities should be at the base of the building, or drains near to or passing through there, the air should be led from a distance from the ground. The woodcut annexed will show how this can be effected. The entrance to the conduit, or " fresh air ventiduct," is below the eaves. In buildings already- constructed, forming these ven- tiducts would be attended with considerable expense, to save which, apertures may be made at the lower part of the walls. And in order to stop as much as possible the ingress of all extraneous particles of dust, &c., through these, there should be stretched across the inside of the opening, sheets of very finely perforated zinc, or horse-hair cloth. Where the air has to be led into the interior of a church, say to the passages, ventiducts must be employed to con- duct the air to the required place. These conduits may be made of zinc or iron pipes ; but a cheaper mode is to make wooden boxes of sufficient size. To prevent the damp from affecting these, the out- sides should be covered with two or three coats of a composition of tar and sand, (three of the former to one of the latter.) The best place, in the gene- PUBLIC BUILDINGS. 27 rality of churches, to lead the air to, is the passages ; and, indeed, in most of other public buildings. The apertures at the place of ingress to the interior should be covered with cast-iron gratings. These can be made of a very handsome design, which may be de- scribed as a parallelogram, divided into diamond- shaped lozenges, by bars ; in the centre of each of which are rosettes, which, passing across the shortest diameter of the diamond's openings, leave the corners at the longest diameters open for the passage of the air. But in order to diffuse the air as much as possible in its passage through the gratings, along the under side of these, plates of zinc, with small perforations, should be fixed, or sheets of horse-hair cloth. For this purpose we would also recommend the adop- tion of " cocoa-nut fibre matting" it is very cheap, porous, and can be made of any closeness of tex- ture : it is becoming much used for the passages and aisles of churches. If used in this way, any species of grating, however rough, would do, as it would be hidden by the cloth laid above it. One thing in connexion with the gratings should be borne in mind, that is, to have the apertures greater, at least equal in surface to those on the outside. Having described the ventiducts for the admit- tance of fresh air, we will now give the valves, for regulating the admission to these, according as it is required; and, first, as to the valve designed for 28 VENTILATION OP the ventiduct, the opening of which is at a distance from the ground. Fig. 1 is a side section of a very simple contrivance for this p- lgt purpose : a a the wall, d the iron staple supporting a bracket for hanging the wheel e ; this bracket is fixed in the wall above the aper- ture, and at its centre ; a chain or rope, c c, is passed over the wheel or pulley e, and attached to the hinged valve b the rope should J be continued till within a short dis- tance from the ground, and provided with a weight at its lower extremity, counterbalancing the weight of the valve b. A glance at the figure will enable the practical man to perceive its action. A variety of contrivances may be adopted for regulating the admission to fresh air venti- Fig. 2. ducts, situated at the base of the walls near the ground we however only give two. Fig. 2 is a representation, in section, of one of these : a a is the wall, b b an iron quadrant fixed in the wall at the end of the aperture 5 this quadrant has a groove or slit, as shown by the dotted line ; this allows a thumb or pinching screw, attached to the hinged valve cc, to traverse up and down therein; the valve PUBLIC BUILDINGS. Fig. 3. is moved by the handle c7, and is fixed in any position by the thumb-screw. Fig. 3 is a front view of what we call the " damp- er valve," as it is made on the same principle as the damper of a steam-en- gine furnace : a is the damper valve, made of sheet of cast or malleable iron, some two or L three eighths of an inch thick, and of size pro- portioned to the size of aperture ; a' a! is the frame, leaded into "the wall, in which the valve plays ; b b small wheels or pulleys round which a chain or rope passes, at the end of which a coun- terpoise weight is fastened, the other end being attached to the damper valve ; d d the wall. The action of the plan is so simple that it requires no further explanation. The apertures for the admis- sion of fresh air should be disposed at equal dis- tances round the building, if possible on all sides, so that, from whatever quarter the wind blows, an aperture may be placed so as to receive its influence : not that the force of the wind is necessary, for air, 30 VENTILATION OF as we have shown, will find its way wherever it is required, unless prevented ; but in windy weather more air will be forced in, in a given time, than in calm weather. Having provided means for the admission of fresh, we will now direct attention to the means for withdrawing the foul air. The apertures for its escape should be placed in all cases at the highest part of the ceiling. We have already hinted at the plan argued by some to be the best, namely, withdrawing the foul air from the bottom of buildings, on the supposition that, as the carbonic acid gas is heavier than common air, it must neces- sarily fall to the lowest portion of the interior. Plausible as this plan seems in theory, in practice it is found altogether erroneous. That this is the case, our notice of the laws of air, which we have already given, abundantly proves. But as there is much doubt, even still, in some cases existing, we here give a remarkable instance of the absurdity of the plan, extracted from the evidence of Dr Arnot before the Committee. " In the Zoological gardens in the Regent's Park, a new house was built to receive the monkeys ; and no expense was spared which, in the opinion of those intrusted with the management, could insure to those natives of a warm climate all attainable comfort and safety. Unhappily, however, it was believed that the objects would be best secured by making the new PUBLIC BUILDINGS. 31 room nearly what an Englishman's drawing-room is. For warming it, two ordinary drawing-room grates were put in, as close to the floor as possible, and with low chimney openings, that the heated air should not escape by the chimneys ; while the windows, and other openings in the walls above, were made as close as possible. Some additional warm air was admitted through the openings in the floor, from around hot-water pipes placed be- neath it. For ventilation in cold weather, openings were made in the skirting of the room, close to the floor, with the erroneous idea that the carbonic acid gas produced in the respiration of the animals, because heavier than the other air in the room, would separate from this, and escape below. When all this was done, about sixty healthy mon- keys, many of which had already borne several winters in England, were put into the room. A month after, more than fifty were dead, and the few remaining ones were dying. This room, open only below, was as truly an extinguisher to the living monkeys, as an inverted coffee-cup, held over and around the flame of a candle, is an extin- guisher to the candle. Not only the warmth from the fire, and the warm air allowed to enter by the openings in the floor, but the hot breath, and all the impure exhalations from the bodies of the monkeys, ascended first to the upper part of the room, to be completely incorporated with the 32 VENTILATION OF atmosphere there ; and by no possibility could escape, except as part of that impure atmo- sphere gradually passing away by the chimneys and the openings in the skirting : therefore, from the time the monkeys went into the room until they died, they could not have had a single breath of fresh air. It was necessary only to open, in the winter, part ot the ventilating apertures near the ceiling, which had been prepared for the sum- mer, and the room at once became salubrious." After this long, but, we hope, not useless digres- sion, we will return to our practical details. A glance at the accompanying sketches will enable the reader at once to perceive the great difference between flat and coved or sloping roofs. The heated air-currents, striking in the flat roof, are driven for a small space downward, creeping along till they reach the ventiduct ; on the contrary, with a slop- ing roof the currents, wherever they strike, are enabled to slide gently upwards to the ventilator, which, in such cases, must be higherthan any part of the roof. The dotted lines show the progress of the currents. If the nature of the building will PUBLIC BUILDINGS. 33 admit of it, the area of the aperture should be distributed over the ceiling in more than one place. Supposing the area of aperture of a church is re- quired to be 3 square feet if three apertures, of 1 square foot each, be placed along the roof at regular intervals, the building will be more speedily ventilated than if one aperture of 3 feet square was alone used. This is evident when we con- sider that the various columns of heated air, in ascending, would have to move towards the one aperture from all parts of the interior; while, if there were more than one, each hole would com- mand a certain space near it of no great area. In cases where there is an inner roof or ceiling thus forming an empty space between it and the external roof the foul air should on no account be allowed to enter in it, as, by spreading itself beneath, and coming in contact with the cold roof, its ascend- ing power will be very much diminished. The plan almost in all churches carried into effect, where ventilation is attempted of having louvres, or spaces in the external roof opening into the space between the roof and ceiling and through the latter to the interior, by the holes made in it is just as wise as that which would be adopted by a miller, who, instead of leading the water to his mill in one large dam, endeavoured to do so by conducting it in a series of little rills or small pipes, regardless of the loss sustained by friction and waste. We have C 34 VENTILATION OF seen, in such cases, apertures or long slits made in the upper part of the ribs or mouldings used in architectural decorations ; but, excellent as this idea appears, it is comparatively useless, inasmuch as the air which does pass through them, entering the large cold empty space, is so diminished and weak- ened in its ascending power as materially to weaken the ventilation, even where proper apertures are made below to admit fresh air. The sketches here given will amply illustrate the superior advantages of leading the foul air through the empty space by means of a wooden or iron box or pipe ; the sketch above is a representation of the old plan we have condemned : the dotted horizontal lines show how the air spreads itself along the space. But, bad as PUBLIC BUILDINGS. 35 this plan is, it is good compared to one we have frequently met with in our practice, in which a ventilator, generally ridiculously small, has been attached to the outer roof, communicating with the empty space, but the inner roof or ceiling provided with no aperture communicating with the interior of the building the interior of the church, with reference to its connexion with the ventilator, being as good as if it had been hermetically sealed. The absurdity of this plan is so apparent that it is need- less to condemn it, otherwise than by the mere men- tion of it. It may, however, be adduced as one of the proofs we could bring forward of the utter ignorance of many architects and builders as to the philosophi- cal principles of ventilation practically applied. In constructing the ventiducts for the with- drawal of foul air, means should be Fig. 4. provided for regulating the velocity of the passing current. Fig. 4 is a sec- tion of a contrivance recommended by Tredgold : a is the ventiduct or wooden box; a board J, ornamented on the under part, larger in diameter than that of the ventiduct, is hung in the manner shown, by a rope or chain passing over two pulleys, one of which runs on a small iron rod stretched across the interior of the box. The other is placed just above the opening made in the ceiling 36 VENTILATION OF near the wall, through which the cord is passed into the interior of the church, and conducted to a height sufficiently easy to be reached by the attendant, and terminated by a counterbalance weight ; b is the valve, c the rod for suspending it, sliding through two holes made in bars stretching across the ventiduct. Fig. 5 is a sec- Fig. 5. tion of a different construction, which we would recommend as convenient and efficient : a a is the ventiduct ; a valve &, made of wood, is fitted to the interior, and hinged at one side. The end for working it passes through a hole cut in the side of the box, and is taken over a pulley, fixed there and supported by a small bracket. The cord is led to the opening in the ceiling, over which is another pulley, on which it rests, and conducted to any part convenient in the interior. In cases where the latter ventiduct is used, the contrivance shown in the an- nexed sketch should be adopted. A piece of wood, considerably larger in diameter than the aper- ture of the ventiduct, (at least one-third,) should be firmly sus- pended about 14 or 18 inches from the opening, according to circumstances. The use of this is very obvious. The opening of the tube, if left open, would PUBLIC BUILDINGS. 37 have a tendency to draw away the column of air only immediately under it ; while, by means of this, the air is drawn horizontally as it were, creating a horizontal current calculated to draw off the whole air near the ceiling. The dotted lines will show the mode of action. The under side of the wood should be ornamented with some light ornaments, properly fixed, as, by falling from such a height, they might seriously hurt those underneath if becoming detached. Great care should be taken to have the board itself properly fastened. As a means of ascertaining the exact degree of opening of the valves, in the foul-air ventiducts, the index-plate, of which the following is a sketch, will be useful. To the counterpoise, ^ .. at the end of the rope or chain ( SHUT \ used in working the valves, have ^ pointers, as at a, attached ; pro- vide a tin plate, cut in the shape as shown at b b ; shut the valve, and on the wall place the tin plate with the upper mark shut opposite the pointers. Then open the valve Tialf^ as may be seen by a party placed near the ventiduct ; at the place where the pointers rest, paint the word half on the tin plate ; do the same at the other two points, quarter and three-quarters, and 38 VENTILATION OF at open. The spaces between these may, for greater accuracy, be divided into equal parts; but this, in the generality of public buildings, will be unnecessary. In ventilating churches, where galleries are con- structed, care should be taken to provide these with a separate supply of fresh air; as, if this is not care- fully attended to, the parties there situated must inevitably breathe air, a portion of which at least must be foul, coming, as it will be forced to do, from the under part of the church. The simplest mode to insure a good supply of air, will be to make apertures in the wall opposite to the passages running down towards the edge of the galleries these should have ventiducts leading directly to holes made in the back part of the steps, gene- rally made in the transverse passages in church galleries. The easiest mode of doing this (taking care to confine the air as much as possible till it is carried to the point of egress) will readily occur to the carpenter who may be employed : the arrange- ments will, of course, vary in almost every case, but the principle is the same. In cases where there is a flat roof running above the galleries, ventiducts should be distributed for the purpose of leading off the foul air these should be smaller than those in the main ceiling. The following may be considered as a fair proportion : Supposing there are re- quired foul air apertures of twenty feet square in area, for a church containing fifteen hundred PUBLIC BUILDINGS. 39 people, the area of apertures for the main ceiling would be in proportion to the number of people in the lower part of the church ; if two-thirds were assembled below, twelve square feet would be the area ; the remaining eight would be distributed over the galleries. The rules for ascertaining the area of exit aper- tures or foul air ventiducts for a church, is as fol- lows : " The power of ventilation,' 1 says Tredgold, " should obviously be adapted to the greatest num- ber of people the building is to contain at one time ; and it is obvious that we had better err in excess than deficit." Perhaps an example, in round num- bers, will afford a more distinct view of the quantity of air it is desirable to change in a crowded room. According to deductions made by the same eminent engineer, four cubic feet of fresh air will be required every minute for each individual ; therefore, when a room contains two hundred people, eight hundred cubic feet of air will require to be supplied, " or a little more than would fill a room nine feet square and nine feet high :" four hundred people would require sixteen hundred, and so on. We are aware that four cubic feet per minute will be, by some, thought to be too much ; Dr Eeid mentions ten cubic feet. It may be as well, however, to give the reasons by which Tredgold was induced to give such a proportion. It has been shown, by repeated experiments, that " a man consumes about thirty- 40 VENTILATION OP two cubic inches of oxygen in a minute, which is replaced by an equal bulk of carbonic acid gas from the lungs. Now, the quantity of oxygen in atmo- spheric air is about one-fifth ; hence it will be found that the quantity rendered unfit for supporting either combustion or animal life, by one man in one minute, is nearly a hundred and sixty cubic inches, by respiration only. But a man makes twenty respirations a minute, and draws in and expels forty inches of air at each respiration ; con- sequently, the total quantity contaminated in one minute, by passing through the lungs, is eight hun- dred cubic inches." The absolute quantity of air rendered unfit for respiration by the perspiration of the body, &c., has not yet been fully ascertained." " It must, at least, be desirable to change as much of the air of a room as the moisture given off would saturate in the same time ; and in a room at sixty degrees, on the supposition that, in consequence of the body being chiefly covered, the moisture given off does not exceed eighteen grains, it will be neces- sary to change three cubic feet of air per minute for each individual in the room." And for the deterioration of air by lighting, he allows one- fourth of a cubic foot per minute for each indi- vidual ; and the total amount he thus obtains is 6416 cubic inches, or nearly four cubic feet per minute. As the rate of ascension of the vitiated air, in the PUBLIC BUILDINGS. 41 tubes prepared for its exit, depends upon the diffe- rence of temperature of the external air, and of that in the tubes, or interior of the building, the greater the difference the greater the velocity of ascent ; it follows, then, that in summer it will be more difficult to ventilate a building than in winter. On the assumption that there will not be a greater difference in summer, between the external and internal air, than ten degrees, Tredgold founds the following rule, " Multiply the number of people the room is to contain by 4, and divide this product by 43 times the square root of the height of the tubes in feety and the quotient is the area of the ventilator- tube" By the height of tubes is meant the height from the floor of the room to the place where the air escapes to the atmosphere. If there are more tubes than one that is, if the area of the exit aperture found by the above rule can be divided, and disposed in more than one, the different venti- ducts should be all of the same height, as, if they are not of the same length, the tall ones will overpower the short, and adverse currents will ensue. The whole of the ventiducts should reach at least 18 inches above the roof from which they project, and be properly finished at top to prevent the wind blowing down them, or rain, snow, &c., descending. The an- nexed figure is an elevation of a top recommended 42 VENTILATION OF by Tredgold, and which has been successfully and largely used : a is the under part for fixing it to the ventiduct. The inside diameter of this should be of size sufficient to slide tightly over the outside diame- ter of the ventiduct, and there firmly fastened by screw-nails ; the cover d made circular or conical, prevents any down draughts; and the angular edges c c create an upward current in the tube, when the wind blows, by the course which it is caused to take. These slopes cc should be made more angular than shown in the sketch. The tops should be made of metal, as zinc or tinplate, well painted black. The tops recommended for chimneys in Chapter V. of this work will do well for furnishing ventiducts. The area of the apertures for fresh air, if the air is led to the passages or interior by tubes or venti- ducts, should be equal to, or even a little less than those of the foul air ; if the air is admitted at once from a simple aperture to the interior, allowing it to spread itself at once, the area should be double that of the foul air ventiducts. The air contracted in the tubes will rush in with greater velocity than simply through an aperture : this will compensate for the difference in size. We have, in these practical details, treated of them as applied to churches alone ; the practical man will at once see how the same suggestions and rules can be made applicable to the ventilation of any public building. We will shortly, however, in con- PUBLIC BUILDINGS. 43 nexion with hospitals, theatres, &c., throw out some additional hints. " No buildings, on an average, are more defi- cient in the means of ventilation than churches. Air, loaded with carbonic acid and the moisture of the breath, and with products from the combustion of gas, oil, or candles chilling draughts from immense surfaces of glass, inequality of heat, emanations from graveyards," may all be observed producing deleterious effects." To these may be added the hot, burnt, and too frequently un- healthy air sent in from the imperfectly con- structed stoves generally found to be used for heating churches. The importance of ventilating places of worship has not been too fully insisted upon. Dr Reid eloquently descants upon the evils of non-ventilation : we would hope that Christian people and Christian ministers will benefit by such remarks, and believe it to be their privilege, as it certainly is their duty, to render the places in which God is worshipped, in every way calculated to assist the reasoning faculties, the intellect of those assembled therein ; and not, as too often is the case, subjecting them to influences affecting not only the body with disease, but the mind with a lethargy and an indifference too painfully con- trasted with the importance of the subject which they assemble to hear explained. " Few spec- tacles are perhaps more melancholy than those 44 VENTILATION OF presented in such cases as these, (crowded, ill- ventilated churches.) The congregation is not unfrequently placed in an atmosphere of extreme impurity, poisonous in its tendency, arresting or interfering with some of the most important func- tions of life, to such an extent that they are occa- sionally suspended for a time, when a temporary death, or fainting, takes place. But what must the state of the mind have been, and how far was it beneficially occupied in the devotional exercises in which it was previously engaged ? The power of the clergyman is often reduced, as well as the attention of the congregation. Too often he does not recognise the darkness of the physical atmo- sphere that at times oppresses all his labours, and counteracts or diminishes his usefulness, as much by the power with which it subdues his own ener- gies, as by the careless indifference which it encourages in his congregation. At the very moment he may be descanting on the pernicious influence of vice, and pointing out the purifying- power of that moral influence which should sur- round the heart, how often are his labours shorn of their power by the physical poison that some- times paralyses the best intention, the indications of which are manifest in the application of the most ordinary tests, and whose influence might be counteracted by means equally simple and effica- cious !" In all cases where it is at all possible, the PUBLIC BUILDINGS. 45 pulpit should be provided with a separate sup- ply of pure air: this may, in most cases, easily be effect- ed. The air should reach the interior of the pulpit by a double box, as it were, with the inside perforated with holes, as shown in the figure by the thick dotted lines. In order to enable the reader to have a distinct idea of the arrangements for ventilating churches, we give two outline sketches of a church. The view in Fig. 1 is a transverse vertical section : b b are the fresh-air apertures cut in the walls, and the basement which supports the floor ; b' b' the en- trance in the passages ; c the ventiduct for the exit of the foul air ; d the top. Fig. 2 is a plan of half of the floor and ceiling : the same letters refer to this as in Fig. 1. The ventilation of hospitals is of the utmost importance. " Imperfectly ventilated, they have in some cases proved a curse instead of a blessing to the miserable patients who have been conveyed to them. That public establishments are known to the medical profession, where, at one time, from the same cause, no case of compound fracture ever recovered ; few or none survived the amputation of a limb ; mortification attacked every wound, however trivial ; while the prostration of strength 46 VENTILATION OF became so great that men, who at first had stood the severest operations without a murmur, subse- Fig.l. Fig. 2. PUBLIC BUILDINGS. 47 quently cried like children from the slightest pain ; and that cases have actually presented themselves, where the apparently lifeless corpse, subdued and oppressed far more by the atmosphere with which it was surrounded, than by the disease to which it was supposed to have fallen a victim, has actually been known to revive after removal to the dead- room a separate apartment, where the play of a wholesome atmosphere, flowing unrestrictedly upon it, revived the fading flame of life, after it was to all appearance gone, and where health and strength were ultimately restored." In ventilating hospitals, particular care should be taken to pro- vide a large supply of fresh air. From the various foetid exhalations to be met with in such places, the quantity supplied should exceed that allowed for churches. We consider that 6 or 8 cubic feet per minute, for each individual, would not be too large a proportion. The ventilating tubes should be distributed in greater number than in churches, and they should be made all of the same height. In some cases, where there are stories ranged one above another, the foul-air ventiducts cannot be passed through the roof, as is done in churches. Apertures can, however, be made in the cornice, leading to air channels, all of which may be led into one large ventiduct situated in the roof of the building, or leading directly (by tubes inserted in the walls) to the eaves below the outside cornice. 48 VENTILATION OF In leading the air thus away, the great desidera- tum is to keep it collected as much as possible not to allow it to spread into crevices or empty spaces. Fresh air should be let into ventiducts formed beneath the floor the apertures for these made in the outside walls, beneath the windows. As birds are often found to build their nests in these holes, bars should be fixed across the openings, or plates of zinc with very large holes, say inch or inch-and-half. The gratings made in the floor- ing should be in the space between the rows of beds, and diffused, in its entrance to the room, as much as possible, by finely perforated zinc, or sheets of horse-hair cloth. It is of great import- ance to have means provided for heating the air admitted to hospitals. In Chapter V. the most simple plan for effecting this will be shown. The water-closets should, in all cases, have separate ventilating arrangements. The ventilation of schools is likewise of great importance. How often do we see the efforts, alike of teachers and taught, paralysed by the atmosphere with which they are surrounded ! In cases where there is no other apartment above the school-room, the same plans we have elucidated in the case of churches can be carried into effect; if not, the plans desci'ibed in Chapter III. should be adopt- ed. One plan we have adopted with great success, where the fresh-air ventiducts could not be led into PUBLIC BUILDINGS. 49 the interior of the apartment, to be there diffused. We caused large apertures, the size of which were proportioned to the number of youths in the school, to be cut in the external walls, right through to the apartment : the bottoms of these ,were flush with the level of the floor. Before each of these apertures we made a circular valve, of tin, with an iron handle to open and shut them much on the principle of the throttle-valve of a steam- engine ; and before these again we placed neatly designed boxes, made of wood, the front of which, between the base and the cornice, was formed of a plate of very finely perforated /inc. The foul-air ventiduct was in the centre of the room, leading through the space between the ceiling and the roof. The edges of the ventiduct in the ceiling of the apartment were ornamented with handsome scroll-work, made of stucco ; and about 18 inches beneath the aperture was suspended, by beautifully wrought gilt chains, an exceedingly handsome lamp, the products of combustion of which were at once taken off by the ventiduct, and served another important purpose of materially assisting the ven- tilation, from the upward current produced by the action of the heated air. As the plan we have mentioned for admitting air is very inexpensive, inasmuch as ventiducts beneath the flooring are not required to be made, and the gratings otherwise necessary dispensed with, we 50 VENTILATION OF give here ample descriptions of the mode of con- structing the valve and boxes. We will suppose the aperture for the admission of fresh air in the wall to be 10 inches diameter. G et a plate of strong tin ; cut out of it a circular disc 12 inches in diameter; in the inside of this, cut out a circular hole 10 inches diame- ter; a flat ring, 2 inches broad, will thus be obtain- ed. Make a hoop of the same metal, 1-^ inch deep, and 10 inches in diameter ; solder the edge of this to the flat ring, in such a way as that the hoop shall stand upright upon it. Cut out a circular disc a little less than 10 inches in diameter, so as to fit easily into the inside of the hoop ; on one side of this solder a strip of angular metal, the length of which may be 8 or 9 inches. In the middle of the rim of the hoop, at opposite sides, punch two holes of an inch in diameter; procure a piece of 8-inch wire, or a little thicker ; insert the plate or valve in the inside of the hoop, so as that the holes coincide with the apertures of the angular strip soldered on the surface of the valve ; pass the wire down the upper hole through the slip, and the opposite hole in the hoop ; hammer the angular strip close down upon the wire, so as to fasten the plate to it. It will be seen that, by turning the wire, the valve may be turned either way : the top of the wire should be bent, so as to coincide with the valve when shut: By punching holes in the outer ring, the valve can be fastened PUBLIC BUILDINGS.' 51 to the wall inside, opposite the aperture. The box placed before this should be made of wood, and ornamented with a neat base and cornice. The flat part of the front between them should be left out, and its place filled with a sheet of very finely perforated zinc. Of course, the wall to which this box is fastened forms the back, and the floor of the room, on which it rests, the bottom ; so that there are only sides, top, and part of the front, made of wood. The handle of the valve should pass up through the top of the box, and bent, so that, when the valve is shut, the bent part lies parallel with the wall. When it is turned at right angles to it, the valve will be open. An index-plate, made of a half-circular form, may be divided into parts, by which the amount of opening of the valve can be easily ascertained. The dia- meter of this index-plate would be parallel to the line of wall, and the mark " Open " would be placed at the extremity of its shortest diameter. These valves are exceedingly useful in cases where the air cannot be led beneath the floor to the inte- rior of the apartment. In ventilating Theatres, it is of importance to remember that " much motion in the central parts would increase the difficulty of hearing." The ventiducts for leading the foul air from the interior should be made near the sides as behind the rows of seats in the boxes, &c. ; the ventiducts being 52 VENTILATION OF within the walls, or placed outside, and covered with ornamental boxes. The ventilator in the centre, beneath the large chandelier, should not Tse too large, and its area rendered greater or less by means of a nicely regulated valve. The galleries should be ventilated by having fresh-air ventiducts proceeding at once from the walls situated at their elevation. These can be easily made, as the galle- ries generally are at the highest part of the house. The foul-air ventiducts should be led at once through the roof to the external air, in the same manner as we have recommended for churches. The pit should be supplied with fresh air by minute apertures made in the flooring, or by long grat- ings, some five or six inches broad, stretching the whole breadth of the pit below, say, every second seat. Means should be provided for heating the air in winter. The boxes should have inde- pendent supplies of air. This can be easily effected by making apertures in the walls, and leading the air at once to the passages, and to the front of the boxes similar to the plan we have already de- scribed for supplying the interiors of pulpits with an independent supply. The stage should be ventilated by a foul-air ventiduct, placed at the extreme back, having at various altitudes, (say the middle, near the top, and the extreme top,) valves easily commanded, opening inwards; through which, when necessary, the products of combustible mat- PUBLIC BUILDINGS. 53 ter used for scenic effect can find their way, and be led off at once to the external air. In the roof, right above the stage, a ventiduct should be placed, and put under proper control. By the adoption of these suggestions, the details of which will vary according to local circumstances, the interior of a theatre may be easily and efficiently ventilated. In carrying out plans for the ventilation of public buildings, there is one thing which should be carefully considered that is, the management of the lights. We have already shown that air is much deteriorated by the products of combustion ; it is necessary, then, to make ample provision for carrying off the products as fast as generated. In our rules for finding the area of the foul-air aper- tures, we have shown that this cause of deteriora- tion has been provided for ; and in cases where our suggestions are carefully carried out, we have no doubt but that the products of combustion will be rapidly carried off. If, however, expense is no consideration, we would recommend the adoption of " exclusive lighting." This may be explained as plans by which the light is confined within a transparent cover, as a pendant suspended from the roof having no connexion with the interior air of the building, but supplied with air necessary for supporting the combustion from the external atmo- sphere, the products being at once led off to the outer air by means of a ventiduct. Practically, it 54 VENTILATION OF will be sufficient to have the light draw its supply of air from the interior of the apartment to be lighted, the foul air being led off to the ventiduct. Such a light as the " Bude " would not only illu- minate an apartment efficiently, but likewise materially assist the ventilation. This subject will be returned to in Chapter III., where further suggestions on this important subject will be given. In noticing the various plans promulgated for the ventilation of public buildings, we would be led into the consideration of a vast number of details, the explanation of which would only take up space, and be somewhat foreign to the scope of this trea- tise, which endeavours to elucidate only what may be easily rendered practicable. While simply referring the reader to study the various details of the plans put in operation for the ventilation of the Houses of Parliament by Dr D. B. Eeid in the perusal of which he will pick up much information that will be extremely valuable we will content ourselves by explaining the process of ventilating buildings by a peculiar fan, recommended by Dr Arnot, a gentleman who has devoted much of his time to the consideration of the subject ; and the recently patented plan of Dr Chowne, the simpli- city of which is its greatest recommendation. Dr Arnot's ventilating apparatus may be briefly de- scribed as an air-pump, provided with cloth valves PUBLIC BUILDINGS. 55 and a piston, which may be easily wrought by a boy, or by the operation of a falling weight. This apparatus may be fixed in the lobby or corridor of the church, taking care to supply this part abun- dantly with air, and the air forced into the inte- rior through the doors, &c. There is no doubt that, with properly constructed foul-air ventiducts, this contrivance is very efficient. In some cases, where it is difficult to provide fresh-air ventiducts, such as we have recommended previously, this apparatus may be used with advantage; but it must be remembered, that it will not give satisfac- tion unless foul-air ventiducts are supplied and properly constructed. Those who may wish to receive further information about it, may obtain such by applying to Mr Edwards, 42 Poland Street, Oxford Street ; and Mr Davies, of 24 Upper Cleveland Street, London, who make the valves to order. The plan patented by Dr Chowne will now be briefly noticed ; and, for this, we give the following extract from the London Lite- rary Gazette : " The improvements are based upon an action in the syphon which had not pre- viously attracted the notice of any experimenter viz., that, if fixed with legs of unequal length, the air rushes into the shorter leg, and circulates up, and discharges itself from the longer leg. It is easy to see how readily this can be applied to any chamber, in order to purify its atmosphere. Let 56 VENTILATION OF the orifice of the shorter leg be disposed where it can receive the current, and lead it into the chim- ney, (in mines into the shafts,) so as to convert that chimney or shaft into the longer leg, and you have at once the circulation complete. The curiosity of this discovery is, that air in a syphon reverses the action of water or other liquid which enters, and descends or moves down the longer leg, and rises up in the shorter leg. This is now a demonstrable fact. . . . That air in the bent tube is not to the surrounding atmosphere as water or any heavier body, is (from the result of this discovery) evident ; and it must be from this relation that the up-draft in the longer leg is caused, and constant circulation and withdrawal of polluted gases carried on." The action of an in- verted syphon is such as is here described. We have experimented with a tube so small as half an inch in diameter, and the heated air was drawn down the short leg, ascending by the long, with conside- rable velocity. If acting with certainty on a large scale, we hail the invention as one of the most important of the day; so simple in its nature, so easy in its application, it really is a boon to the commu- nity. The phenomena exhibited, however, by this invention, have been observed and commented upon many years ago. Desaguliers described a smoke- consuming stove, consisting of a fire in the short leg of a syphon, the long leg drawing the smoke PUBLIC BUILDINGS. 57 down through the burning coals, and up the long leg. Dr Franklin says, " Such a machine is a kind of inverted syphon ; and as the greater weight of water in the longer leg of a common syphon, in descending, is accompanied by an ascent of the same fluid in the shorter, so in this inverted syphon the greater quantity of levity of air in the longer leg in rising, is accompanied by the descent of air in the shorter." The plan is, however, in direct opposition to that recommended by Tredgold. We will notice this more fully in the succeeding chapter, concluding our remarks by again quoting from the same writer above, in connexion with this important discovery : " We see no end to its application. There is no sanitary measure sug- gested to which it may not form a most beneficial adjunct. There is not a hovel, a cellar, a crypt, or a black coal-hole anywhere that it may not cleanse and disinfect. We trust that no time will be lost in bringing it to the public test on a large scale ; and we foresee no impediment to its being immediately and universally adopted for the public weal. We ought to remark, that fired or heating apparatus are not at all necessary ; and that, as the specification expresses it, ' this action is not pre- vented by making the shorter leg hot while the longer leg remains cold, and no artificial heat is necessary to the longer leg of the air-syphon to cause this action to take place. Extraordinary as 58 VENTILATION OF this may appear, we have witnessed the experi- ments made in various ways, with tubes from less than an inch to nearly a foot in diameter, and we can vouch for the fact being perfectly demon- strated. Light gas does descend the shorter leg when heated, and ascends the longer leg where the column of air is much colder and heavier." In applying this invention to the ventilation of public buildings for instance, a church due care should be taken to supply the interior with a sufficiency of pure air for the principle we formerly enunciated, relative to the withdrawal of foul, will apply in this case as in all others. The short leg of the syphons should be placed at intervals in the walls, in the ceiling above the side aisles of the church, imme- diately beneath the galleries, and also above the galleries the wooden ventiducts we have formerly explained being placed in the main ceiling above the body of the church. The rules for ascertaining the area of the apertures of the syphon tubes will be the same as we have already given so much of the whole amount required being allotted to these, and the remainder to the ventiducts in the main ceiling. In buildings already constructed, enclos- ing the legs of the syphons in the walls would be attended with considerable expense ; they can be fastened to the exterior, and concealed with orna- mental coverings. Before putting this plan into effect, liberty to adopt it must be granted by the PUBLIC BUILDINGS. 59 patentee his discoveiy being protected by letters- patent. Architects will easily perceive, that, by the adoption of the plans we have recommended, not only will buildings be effectually ventilated, but in a great measure, if not altogether, dry- rot in the timbers will be prevented, by the free circulation of air in the lower part of the build- ing a desideratum of considerable importance. And, in planning new constructions, we would earnestly recommend them to adopt, from the very first, efficient contrivances for securing ven- tilation. Architects have much in their power ; and we humbly conceive that, when fully aware of the importance of the subject, they will not be apathetic or indifferent to the application of simple, effectual plans. In regulating the operation of ventilation effected by simple openings, provided with valves, such as we have described, the attendant should pay atten- tion to the number of people assembled in the inte- rior of the building, and so open or shut the valves accordingly as it is evident that the same area of aperture will not be required for five hundred people as for a thousand. The index-tables we have figured and described, will be of service in enabling him to adjust the valves ; they may be attached to the fresh-air ventiducts as well as to the foul. If he calculates the church to be half full, he will put the 60 VENTILATION OF PUBLIC BUILDINGS. balance index-weights at the mark " half" in the table, and so on in proportion ; and he should make a little allowance in the day-time, by shutting slightly the valves, as the lights are not in use. It is to be observed, that the whole area of the apertures fixed by the rule we have given, applies to the maximum number the building is to contain. The fresh-air ventiducts should be shut or opened in the same proportion as the foul air. Attention to these rules is necessary, as, supposing half of the congregation only was assembled, if the ventiducts were wholly opened, in all probability there would be a descending current coming down one side of the foul-air tube, and an ascending current at the other, the area being too great for the body of air to pass through it. By a little experience the attendant will soon be enabled to regulate the ven- tilation with considerable precision. CHAPTER III. VENTILATION OF APARTMENTS IN DWELLING-HOUSES, SHOPS, &C. " I praise the man who builds High on the breezy ridge, whose lofty sides The ethereal deep with endless billows chafes. His purer mansion, nor contagious years Shall reach, nor deadly putrid airs annoy." ARMSTRONG. THIS part of the subject has been unfortunately invested with many apparent difficulties, arising, doubtless, from the promulgation of so many dif- ferent plans ; the details of which, complicated, in appearance at least, however simple in principle, have had the effect rather of deterring the majority of people from attempting the ventilation of their apartments, than inciting them to the attainment of information in connexion with the subject, and, of course, a desire to be supplied with efficient means to secure good ventiliation. This is the more to be regretted, as it is a matter of no small importance that there should be a large quantity of air supplied to the interior of the apartments 62 VENTILATION OF APAETMENTS IN in which individuals habitually reside. Important as is the ventilation of public buildings, compared with that of dwelling-houses it is of little moment ; it is only at intervals that people assemble in large numbers in their own dwelling-houses they are constantly exposed to the atmosphere therein, which, in nine cases out of ten, is foul and impure, and in consequence the cause of much illness and disease. In treating of this subject, we will en- deavour, as far as possible, to divest it of all its difficulties, and explain, briefly and practically, the simplest modes of ventilating apartments. The first thing to be considered is the supply of pure air ; and particular attention should be paid to the source from whence it is derived. Too fre- quently, in consequence of the defective condition of drains and sewers, the air around our dwelling- houses is very much contaminated. If such de- stroyers of the purity of the fresh air should be situated near the house to be ventilated, the air should be drawn at the greatest possible distance from them. In supplying houses with air, there are two modes by which it may be effected by supplying the lobby, hall, or central staircase with a large amount, or each separate apartment with a quantity sufficient for its size. In all cases where the architectural arrangements will admit of it, we would recommend the latter mode to be adopted ; by the former, from the multiplicity of currents, DWELLING-HOUSES, SHOPS, ETC. C3 produced by the doors and windows having con- nexion with the central staircase, &c., the risk will be run of one room taking a larger supply than another, thus depriving one of its proper quantity. That this may be the case is likely, when we con- sider that a drawing-room, for instance, might draw its supply from a contiguous apartment, the egress being easier than from the hall : in very large mansions, however, the first mode may be easiest adopted. We will first consider the mode of sup- plying each room, independently of the others. Let an aperture of sufficient size (calculated according to the mode given in Chapter II.) be made in the outside wall, beneath the window. To preserve a neat appearance, the area required may be divided into several parts, and corresponding apertures made in the wall the neatest form will be an oblong, somewhere about six inches long, by one and a half broad. These apertures should be cover- ed, on the outside, by plates of perforated zinc. From where these apertures communicate with the interior of the apartment, let the skirting board be pierced with numerous small holes, and the inside of these covered with perforated zinc, or hair-cloth, or left open, as when bored with a gimlet. Instead of admitting the air at the skirting board, it may be led to the centre of the apartment, where the table stands, the floor being pierced with holes to permit its egress : the carpet of the room would 64 VENTILATION OF APAKTMENTS IN serve to diffuse it. Again, it may be led to the wall opposite the fire-place, and admitted by aper- tures in the skirting-board. In cases where the building is being planned, the architect should in- corporate ventiducts in the interior of the walls, leading from the outside, below the eaves or bottom of the cornice or coping, as v shown in the figure in Chapter II. In cases where these modes of admit- ting air are not available, the plan which we will now describe should be adopted. The sheets of perforated zinc used by J. Toynbee, Esq. and by the Samaritan Fund, are cheap and simple. The pane of glass farthest from the fire-place, and in the upper row, is taken out, and its place supplied with a sheet of zinc, having two hundred and twenty perforations to the square inch. Panes of perforated glass are now made for this purpose they may be obtained from Mr Bowie, No. 1, Fowkes Buildings, Tower Street, City, London. The glass louvres, patented by Bailley, are exceed- ingly handsome, not very expensive, and thoroughly efficient. We here give a description of a plan for making tin louvres or window ventilators. Take a sheet of tin, the size of the pane of glass to be removed ; cut long apertures, as shown in the sketch, at a, of length very nearly equal to the DWELLING-HOUSES, SHOPS, ETC. 65 breadth of the plate, and quarter of an inch, broad ; to the bottom side of these slits, which should be three-eighths of an inch apart, solder strips of tin, the length of the aperture, and three-eighths or half an inch broad, inclining upwards, as seen at I b. According as the wind or air is required to be thrown into the room upwards or downwards, so should the tin-plate be inserted in the frame, with its louvres inclined accordingly. In the sketch it is shown as fixed to throw the air upwards, the dotted lines showing the course of the air. In supplying fresh air to the lobbies, halls, or central staircases of large mansions, from which all the apartments are to be supplied, care should be taken to have the quantity sufficient in volume. It will materially assist the ventilation if the air is warmed as it is admitted ; in Chapter V. we will show how easily this may be effected. The air should be led to the floor of the hall, in which aper- tures may be made to allow it to pass through ; or it may be taken to the back of the skirting, or beneath permanently fixed tables, the fronts of which should have plates of perforated zinc. If the stair- case is provided with a skylight, this should be kept carefully closed ; the desideratum, in such cases as we are now considering, being, to supply each apartment with means of withdrawing the used air, so as to draw their supply of pure air from the central magazine ; not only ventilating themselves, 66 VENTILATION OF APARTMENTS IN but also the staircases, passages, &c., these being supplied with fresh air from the central magazine. If the skylight was left open, thus creating a power- ful upward current, the flow of air into the apart- ments would be materially retarded, if not in some cases altogether stopped. In some instances the withdrawal of the foul air has been recommended to be effected by the skylight, or an opening in a similar position. Now the obvious effect of this arrangement would be, we opine, a constant struggle, if we may so express it, between the currents of fresh air endeavouring to obtain admission to the apartments, and the stronger upward current of air produced by the great opening above, pulling them backwards. Doubtless, the currents of fresh air would be at the lower part of the doors, &c. of the apartments, while those of the foul would be at the top thus, certainly, separated ; still, as we have be- fore said, the natural flow of the fresh air currents would, in such a case, be materially retarded. In our way of thinking, taking away from a magazine of air, as fast nearly as it is introduced, is scarcely the most effectual mode of keeping the supply con- stantly at its maximum ; fresh air is introduced to supply the apartments connected with such a maga- zine, and it should alone be used for such a purpose. The skylight or other opening is not required to ventilate the staircases, &c., as may be affirmed, it being obvious that such will be effected by the DWELLING-HOUSES, SHOPS, ETC. . G7 apartments connected with them these being sup- plied with ventilating arrangements for withdraw- ing air, by which a constant current will be kept up the rooms drawing their supply from the central magazine in the staircase, hall, or lobby, as it may be ; while it, in its turn, draws its own supply from the external air through the openings provided for it. There is one danger connected with this plan of supplying air to the apartments of large mansions, worth being noticed ; this is, if each apartment is not properly ventilated, the foul air from it will obtain access to the central magazine whenever the door is opened, its egress through such being easier the air in the central magazine being thus contaminated. Again, some apartments may, from more powerful ventilating arrangements, draw their supply from another apartment ; this shows the necessity of having the supply to the central magazine ample. If the mansion consists of many stories, each landing may be supplied with a sepa- rate supply of pure air, independent of the open- ings in the hall previously mentioned. This may be effected by making apertures in the outward wall at such places ; indeed, it would be well for every passage or corridor to have thus an independent supply. The openings for admitting the fresh air to the apartments should be near the floor, behind the skirting which should have perforated zinc, or the wood pierced with numerous small holes ; or it 68 VENTILATION OF APARTMENTS Itf may be led to the centre of the apartment, as formerly noticed. Of the two modes of supplying air to the interior of apartments, we think that we have shown enough to prove the superior merits, where attainable, of the plan of supplying each apartment, independently of the others. Rooms thus managed will act well, they will draw in as much air only as they require, and be subject to no opposing influences. Of course, in this mode, the staircases will require to be ventilated separately, the fresh air being supplied at the lobby, and the foul air extracted or withdrawn by an opening at, or near, the skylight. Care should be taken to have this upward current gentle and easy. The next operation we have to consider is the withdrawal of the used air from apartments, to which the plans we have recommended for applying fresh air have been applied. A valve for this pur- pose, highly recommended by J. Toynbee, Esq., and very efficient when properly adjusted, may be used. It is a simple modification of Dr Arnot's plan, which we may term the " suspension valve." Mr Toynbee describes it as follows," It consists of a square iron tube, of from three to six inches dia- meter, and so long that the outer orifice should be flush with the wall of the apartment, and the inner one enter the chimney. These tubes are usually from four to six inches in length. At the orifice entering the room, there is either a plate of perfor- DWELLTNG-HOUSES, SHOPS, ETC. 69 ated zinc, or a piece of fine wirework, from the upper and back part of which hangs a piece of ordinary or oiled silk, which acts as a valve, so as to allow the warm and vitiated air to pass up the chimney, and prevent any smoke from entering the chamber. The accompanying fig- ure will give a good idea of this valve: a a is the iron box, c o the flap of silk, d d the wall of the apartment. The cost of the valve, including the fitting up, is 3s. Of the efficiency of these valves, Mr Toynbee makes the following statement, " The effect on the health of the patient, I have observed, is to accelerate the cure, and to alleviate the symptoms, so as to give great comfort to the patient. The people remark that the ventilation has carried away the smells, and purified the place. I am now continually applied to, by the friends of those whose rooms have been venti- lated, to bestow upon them a similar boon." And here we would direct attention to a fund which has been the means of doing good to a considerable extent, amongst the poor classes of two parishes in London we allude to the Samaritan fund in con- nexion with the St George's and St James' dis- pensaries, which was established for the purpose of supplying the sick poor with flannels and nutritious food, and for ventilating their apartments. In the latter way, the committee have declared it to be 70 VENTILATION OF APARTMENTS IN their opinion that ventilation is one of the most important curative means. We trust that this institution will have many imitators throughout the kingdom. Those wishing for further informa- tion, in connexion with its management and opera- tion, by writing to Joseph Toynbee, Esq., the honorary secretary, 60 King Street, Golden Square, will, we have no doubt, be supplied with every necessary particular. A modification of the suspension valve is made with metal valves, very nicely suspended, and movable with the slightest current. We have hung them so delicately, that the valve has been moved by a breath so faint, that the only indication of our having breathed at all was by the movement of the valve, and the condensation of the breath on the polished brass front. They are made in a very superior style by Mr Edwards, Poland Street, cost- ing from 7s. 6d. upwards ; they are also made in various styles by J. Allen, 22 Guildford Street, Wilmington Square, London. In fixing them, great care should be taken to suspend the valves accurately, as, if this is not attended to, smoke is apt to come into the room. In some instances, the upward current in the chimney is not sufficient to open the valve ; but by adopting the plan of sup- plying fire-places with air, as explained hereafter in Chapter V., they will act sufficiently in all cases. Tredgold gives an explanation of a plan by which DWELLING-HOUSES, SHOPS, ETC. 71 the foul air may be withdrawn from the interior of apartments ; we give it here : " If. an inverted syphon be placed with one leg in the chimney, so near to the fire that the air in that leg will be warmer than the air in the other leg, motion will take place ; for the air will ascend in the warm leg and go up the chimney, and a descending current in the cool leg will take the air from the room. To render the application of this principle successful, the mouth of the tube should be at the ceiling of the apartment ; the lowest part of the curve should be, as much as convenient, below the point where the heat is applied ; and the aperture through which the air flows into the chimney should be formed, so that the soot may not fall down the tube : also the mouth should have a register to close it, or regulate the ventilation. Such a tube may be easily placed in the angle of the chimney breast, or let into the wall. The branch or leg which goes up the chim- ney should be brought so near to the fuel of the grate as to receive a considerable portion of heat." Of this proposed remedy Mr Tredgold says, "I have little doubt it will be in a great measure effective." The new mode of ventilating apartments, patented by Dr Chowne, formerly described in Chapter II., is in direct opposition to this plan of Tredgold's. The only effect of such would be the drawing of the smoke from the chimney down the short leg, and into the room through the long one 72 VENTILATION OF APARTMENTS IN a process by no means desirable. If the reader will turn to Chapter II., where we described this plan, he will see that, however much the short leg was heated, the ascending current in the long one would still continue. From the conclusive experi- ments which have been made, and from the fact that the principle has been successfully applied in the ventilation of buildings, we would recommend, in cases where it can be adopted, a trial of Dr Chowne's patent. As an efficient modification of Dr Arnot's prin- ciple, we would recommend the adoption of the following plan. There is considerable difficulty frequently to place the suspension valve correct- ly, and, unless well adjusted, the smoke is apt to come into the room. With this, however, no one can have the slightest difficulty in the adjust- ment, and no smoke can possibly enter the room through it. Make a hole in the wall of the apart- ment, six inches beneath the cornice above the fire place this should be of size proportioned to the capacity of the room ; measure from the outer edge of the aperture to a point as near as possible in the centre of the chimney flue ; make a tin tube, as re- presented at a, of this length, and put a cover b in the end, which is to be in the chimney ; pass this through the aperture, which, of course, must be made large enough to admit the cover ; when the edge of the tube is flush with that of the aperture DWELLING-HOUSES, SHOPS, ETC. 73 in the wall, solder a plate of plain or ornamented brass, with a flange, to the edge of the tin tube, very tightly : the flange should be of breadth suffi- cient to cover the vacant space of the aperture in the wall, (caused by the difference of size between it and the tin tube,) by at least one inch the cen- tral aperture of the flange being equal in diameter to that of the tin tube ; Roman cement should then be applied all round the edges of the flange, in order to make the passage to the chimney only through the interior of the tin tube. The outside edge of the flange should be surrounded with a neat scroll-border of stucco ; to mask the entrance to the tube, an ornamented wire-grating might be fastened before it : thus ornamented, the ventilator would present no unsightly appearance. The dotted lines in the figure show the current of used air > drawn from the apartment, * 1 by the ascending current in the chimney. In the event of smoke being driven down the chimney, it cannot possibly enter the tube, as (the course of the arrows showing such) it will be deflected from the openings by the angular coverings attached ; more- over, by adopting the plan shown in Chapter V. the occurrence of down draughts in the chimney will be effectually prevented. (See Eecapitulatory Remarks, at the end of Chapter V.) The annexed figure will 74 VENTILATION OF APARTMENTS IN show how highly ornamental to the general arrange- ments of a room, the apertures of ventilators may be made. The ventilators we have described for extracting the used air from apartments, will act most efficiently when there is a fire in the chimney with which they communi- cate. This, however, will not be the case in summer, when ventilation is required very much. If, however, the supply of fresh air is properly managed, all that is necessary to do is to open the valves of the suspension- valve ventilators, and a current of air upwards will soon be estab- lished in the chimneys such being in summer foul- air ventiducts alone ; in winter, ventiducts both for smoke and foul air. The tube we have described will act in all cases without any alteration. Dr Chowne's ventilators will also act in summer equally as in winter. An architect of some note communicated to the- author a plan for ventilating apartments, which he had applied to gentlemen's villas with some success. It must, however, be incorporated with the building when first constructed. At the ceiling of the apartment, above the cornice, he makes a narrow opening ; this communicates with a channel formed between the lath and plaster, and the beams in DWELLING-HOUSES, SHOPS, ETC. 75 which the laths are nailed. The foul air is led through these to apertures formed on the outside walls beneath the eaves, thus affording for it a clear escape from the room. The fresh air is admitted by openings made in the skirting of the room, or in the floor in the latter case, the carpet covers the apertures, and serves to diffuse the air. In this plan, each room must have one independent channel for the egress of the foul air. There are some practical difficulties connected with this plan, which will militate against its general adoption ; however, with an ample supply of fresh air, there is no doubt that it will in a great measure be effectual. In private apartments, the management of the lights is of great importance. In cases where gas is used, the products of combustion should at once be led off ; where candles and table-lamps are chiefly used, the products will be carried off by the ventilation ; but all fixed lights, suspended invari- ably beneath a certain portion of the ceiling, should have means by which their products are instantly removed. " In considering, " says Dr Reid, " the influence of the products of combustion formed during artificial illumination, even where no pecu- liar impurity is presented, it will be noticed that they are as destructive and offensive to animal life as those formed by ordinary fires. It is desirable, accordingly, to discharge them by a chimney or some other means, in the same manner as those 76 VENTILATION OF APAETMENTS IN from the common fire. But where the amount of illumination is small, and the apartment is otherwise ventilated, the amount of moisture and carbonic acid may be too trifling to render this necessary. . . Gas, when pure, does not evolve, during combustion, products that are more offensive than wax, tallow, or oil ; but, from its economy as an illuminating power, a large amount of it is in general used where it is in- troduced as a substitute for other lights. Further, all rooms lighted with gas, where special arrangements are not introduced for ventilation, are subject to the evolution of minute portions of unconsumed gas. ..'.; * . Another peculiarity connected with gas lights, burning in ordinary apartments, requires spe- cial attention viz., their extreme tenacity of com- bustion. Gas lights burn for a considerable time in atmospheres so loaded with carbonic acid, moisture, and nitrogen, as to extinguish oil-lamps and can- dles, or to render their combustion extremely feeble : they do not, therefore, so promptly indicate a gra- dually deteriorating atmosphere. The nature of the gas-burner used also affects the duration of the flame in the vitiated air. The reason of this pecu- liarity in gas is abundantly obvious, on consider- ing that an ordinary gas-lamp is provided with gas already formed, by the action of heat ; whereas oil, wax, and tallow, require heat for the production of the gas beyond what may be necessary for its com- bustion. . . . All vitiated air from oil-lamps or DWELLING-HOUSES, SHOPS, ETC. 77 other lights, if not constrained in its movements by any local current, passes directly towards the ceil- ing of the apartment in which they are placed; recoiling or descending from it as successive por- tions of warmer air displace it, and as it is subse- quently involved in streams of fresh air passing; from doors or windows to an open fire. According- ly, all air above the level of the discharge may be intolerable, and loaded with the products of combus- tion, while a less impure atmosphere prevails below." When a candle or single lamp is used in a well- ventilated apartment, the products diffused through the atmosphere above them will be led off by the ventilators. This may also be the case with gas lustres or chandeliers suspended, as is usually the case, from the centre of the ceiling ; but it is im- portant that these, especially when much light is obtained from them, should be provided with separate foul-air ventiducts, " as much heat is deve- loped, and the radi- ant hoat which tli^y 'i ' - '' -- 1 ' - 'd, ' emit is of consider- able amount, even 1 though the products of combustion be car- ried away." The ^ C "^\ 11 : * tSr* annexed figure will explain a simple method of carrying away the pro- ducts : a is the main tube of the chandelier; b b the 78 VENTILATION OF APARTMENTS IN jets ; c c the circular ornament; d d the cap by which the heated air is caught and deflected into the tube e e. This tube may be led between the ceiling at once to the chimney in an independent air channel ; or, to save expense, it may be led along the outside of the ceiling, and ornamented as it stretches across the roof to the chimney. The cap d d may be made highly ornamental a handsome addition to the decorations of a room, rather than an unsightly ob- ject the clamshell might be designed as one. In shops, the adoption of means for withdrawing the products of lamps has met with great success " silversmiths find that these tubes prevent' their plate from tarnishing; silk-mercers their goods from fading ; ironmongers and cutlers their wares from rusting." These tubes " ought to be universally adopted, and above all, no bakers, butchers, grocers, or provision dealers, should be without them." We give here an illustration of a simple inexpensive kind, which may be fitted up in every shop with advantage. If there is no air-flue to which the products can be led, the tube from all the lights may be led along the ceiling to an aperture in the outer wall, at the front or back of the shop : if in the front, the aperture should be covered with an ornamented grating ; if at the back, a cowl or cover, as shown in the cut, may be used with decided advantage : a a a are the gas lights ; b b b the caps or covers ; c c the flue or tube ; d d the wall ; e the DWELLING-HOUSES, SHOPS, ETC. 79 cap or cowl ; the dotted lines show the course of the currents. The lights used in the illumination of shop windows produce much air that acts very deleteriously on the goods exposed for show. The annexed sketches will explain how this may be obviated: At the upper row, in the window, have Baillie's transparent glass ventilators fixed in each pane ; from the head of the frame a a, have an angular board ornamented on the under side, sloping downwards, as shown at e ; c c represents the tube from which the jets d d are supplied with gas ; b b the glass ventilators; the dotted lines show the course of the currents; the heated air striking upon the board e is deflected upwards, and is passed out through the spaces of the ventilators. The board should be of sufficient breadth to reach 80 VENTILATION OF APAKTMENTS IN beyond the line of gas jets, at least four or six inches ; and, if made of a neat design, it will rather be ornamental than otherwise. It might also be made curved, and its lower edge neatly carved, or sup- plied with small Gothic pendants, which would add much to the decorative appearance of the window. (See Recapitulatory Remarks.) In ventilating workshops in which there is a cen- tral stove, a supply of air, independent of that for the rest of the apartment, should be given to it ; and the tube from which (by which the smoke and heated air is carried away) should be led through the ventiduct placed in the roof of the apartment, if the arrangements of the structure will admit of it. In some shops, stoves are used both summer and whiter, thus affording a great help to the ventila- tion at all times. The gas lights should all be pro- vided with tubes to lead off, at will, the products of combustion. The plans we have explained can be made available, in almost every case, at a very moderate outlay. As in many cases the poorer classes shut up the ventilators, impressed with the absurd idea that they are dangerous, William Hos- king, Esq., proposes the following plan, which can- not fail to be effectual : " A sweet air flue should be made within the outermost jamb of every chim- ney breast, from the bottom to the top, and opening into the outer air free from all communication with the smoke flues, and not liable to be contami- DWELLING-HOUSES, SHOPS, ETC. 81 nated by them. This should open out at the lowest level again either directly under the floor, or by a horizontal flue with a grated mouth so that it may be fed with air from both ends. Ninety-nine out of a hundred would never suspect the mode of access of the outer air, and they would breathe fresh air in spite of themselves." Mr Hosking conceives that the current of air, produced by the air flowing up the chimney, will create currents from all parts of the room thus freeing it from the foul air. Now, we by no means agree with him in this view of the matter; it is contrary to general experience. If it was correct, we would find all apartments well ventilated in which common grate fires were in operation. This is not found to be the case, the fires invariably drawing their supply from below scarcely, if ever, exerting an influence above the zone of respiration. And that such is the case is fortunate ; if not, one bad effect would be the drawing of the current of foul air past those sitting round the fire-place. In adopting, then, this grate of Mr Hosking's, let a ventilator, such as we have previously described, be applied. In Chapter V. we will give a plan and description of a method similar in principle to that of Mr Hosking's. In ventilating apartments, great attention should be paid to that of the bedrooms. On this subject Sir James Clarke remarks, " Nothing, indeed, can be constructed on a worse principle than the bed- F 82 VENTILATION OF APARTMENTS IN rooms in this country generally are. Their small size and their lowness render them very insalubrious, unless well ventilated; and the case is rendered worse by the close windows and by the thick cur- tains with which the beds are so carefully sur- rounded, as if to prevent the possibility of the air being renewed. The consequence is that the occu- pants are breathing vitiated air during the greater part of the night that is, during almost one half of their lives." In such cases, it may well be said, " that the atmosphere in the morning smells more like that of a charnel-house, than an apartment fit for the repose of human beings." We would earnestly recommend means of ventilation to be carefully attended to : if people will not go to the expense of the arrangements mentioned, let them, while absent in the day, have the windows opened, and at night a small portion of the upper sash, say 4 or 6 inches, let down. To diffuse the air thus let in, a plate of perforated zinc 8 or 9 inches broad, and length sufficient to stretch across the window, may be easily attached every evening. Care should be taken that the window thus opened should not be situated right above the bed. Thick curtains should not be used. If the housewife thinks these unwholesome appendages absolutely necessary, let her adopt them of open gauze or net: if a bird suspended in its cage at the top of a bed, within close curtains, is killed by the foul air collected DWELLING-HOUSES, SHOPS, ETC, 83 there, it cannot be healthy to allow the same to act upon the human frame. Having thus briefly described efficacious and easily attainable modes of ventilating apartments, independently of all casual means, we would, in conclusion, recommend every one, in addition to the adoption of these, to ventilate the apartments by opening, on every possible occasion, their doors and windows. Too large a supply cannot be obtained. The currents produced by such are health-giving and health-restoring draughts. There is much nonsense promulgated about the danger of draughts. We have many a long summer day sat in a draught, so thorough and strong that our papers had to be retained on the table by books or weights, or they would have been blown away ; and throughout the whole of the cold months of this confessedly severe winter, we have sat for hours writing, in a draught sufficient to cause a very considerable deflection of the flame of the candle we used in the evenings ; and we will venture to say that no one has enjoyed so singular an immunity from colds as ourselves, although (the air admitted not being diffusively warmed, save through the local action of the fire) the extremities farthest from the fire were on many occasions perfectly benumbed with cold, such being the rapidity of the current of cold air ; yet we have not had the slightest vestige of a cold. Even now, as we write, we can feel the pure fresh 84 VENTILATION OF APARTMENTS IN air perceptibly passing us ; and we hail it as a boon, knowing that it is the very principle upon which our healthy existence depends. Many, very many, are in the habit, moreover, of exposing themselves similarly without incurring any colds, &c. In India, draughts are the very life of the inhabitants, and are artificially produced. We do not assert that people can all at once subject themselves to the in- fluences of draughts with impunity ; with the habit of living in close, confined, over-heated apartments, no wonder that many catch cold on being exposed to a draught. On this Dr Reid says, " The greater the degree to which the movements of the air have been reduced, the more does the system become sensitive to any renewal of its wonted action ; and that the best means of obviating these effects, which are so much dreaded, consist in so regulating the movements of air that it shall never be reduced excessively ; and thus the system can never be heated up to that point when draughts and cold currents become dangerous as well as offensive." In other words, that, by exposing the body gra- dually to the influence of healthy currents, in process of time, the system becoming more equally maintained in temper, changes are neither so fre- quent or so deleterious in their effects. On this subject Dr Reid has further remarks worth notice. He says, " It would be well for those who suffer from draughts and currents, and who constantly DWELLING-HOUSES, SHOPS, ETC. 85 declaim against any movement of air, to consider that their bodies have been so formed that the air never stagnates round them during life ; that a slow, but equal and continuous current ever moves round the living frame; that it is not the mere movement of air which is the cause of offence, but the movement of air in proportions of a character uncongenial to the condition of the system at the moment ; that even the most delicate ladies, who express their horror of draughts and currents, prac- tically increase from time to time the movement of air that infringes upon them in warm atmospheres with their fans, producing an agreeable and refresh- ing atmosphere with air which is oppressive and offensive, when not assisted by their inordinate movement.' 1 A walk in a gentle breeze often cures a head- ach, the party little dreaming that the cure was easier obtained that a window lifted, or a door opened, would have had the same effect, by esta- blishing a thorough current of air through the room, the want of which was in all likelihood the cause of their complaint. Parties are advised to travel for their health, and leave home and all its comforts, submitting to heavy expenses and innumerable dis- comforts, to obtain that which the expenditure of a few shillings at home would have supplied them with fresh air. For it cannot be denied that the chief benefit derived from travel, is the almost constant 86 VENTILATION OF DWELLING-HOUSES, ETC. exposure to fresh air, or, as popularly expressed, " the change of air." To people of very delicate constitutions, it would be highly dangerous to sub- mit themselves suddenly to draughts and cold currents ; but we are certainly of opinion that the majority of individuals are by far too particular in this respect. But, though advising all to open their doors and windows, we would at the same time earnestly recommend every one, as health is valued, to have a plan of ventilation, independent of all such casual means, instantly carried into effect. Not taking into account the injurious effects of foul air on the body, we cannot conceive, even as a matter of taste, how people should prefer foul and foetid to the sweet air, "That trembling floats from hill to hill, From vale to mountain with incessant change Of purest element !" We will close this part of the subject by ex- pressing a hope that our remarks will tend, in some measure, to direct more particular attention to this important subject of domestic ventilation. CHAPTER IV. VENTILATION APPLIED TO AGRICULTURAL STRUCTURES. " Each ambrosial breeze That fans the ever undulating sky, . . . whose fostering power regales Man, beast, and all the vegetable reign." ARMSTRONG. A PEOPER supply of fresh air is as necessary to the health of the inferior animals as it undoubtedly is to man. Baneful as is the influence of impure air, on the constitution of human beings exposed to its influence, it is no less so to the valuable animals the horse and the cow. Many are the diseases which affect our domestic animals, brought on by exposure to foul air ; and many a valuable animal is sacrificed to close and ill-ventilated stables and other structures. Before proceeding to the explanation of plans for ventilating agricultural structures, we will devote a small space to the mentioning of other arrange- ments, which, though they may be considered as somewhat foreign to our more immediate subject, will be of some use to those having an interest therein. 88 VENTILATION APPLIED TO In the construction of a proper stable or cow- house, we conceive four points are necessary to be considered. These are 1. Sufficiency of space in the stalls. 2. Proper methods of ventilating and heating. 3. Proper drains and reservoirs, by which all exuviae can at once be carried off (so as not to vitiate the air in the interior,) and in which they may be collected and preserved for manure. 4. A properly arranged series of water-pipes and reservoir, so as to be available for clearing the whole range of stalls, and to provide a supply for the animals' use. Passing over the first as sufficiently obvious although important to be remembered, and as hereafter to be treated of we shall give a few hints in connexion with the two last. We would recommend all the stalls to be made sloping at a certain angle from the head towards the foot. This slope may be one foot in every eight. At the bottom part of the incline, a pipe or covered drain should be placed in front, running along before all the stalls, and should have a considerable fall or incline throughout its whole length, towards a convenient part of the building, where it should communicate with a larger pipe or covered drain, which should lead to a reservoir for liquid manure placed in the back-yard of the building. The liquid manure will flow down these pipes or drains to the reservoir. AGRICULTURAL STRUCTURES. 89 As the liquid collected from the stalls forms a very excellent manure, it is of importance that proper methods should be adopted for collecting and preserving it. As a most effectual means, we re- commend the power of running water to be used in the following manner : Thefloor of the stall should be made of asphaltum, or be closely flagged, (not floored with small stones, as dirt is exceedingly apt to collect between the interstices.) An iron pipe of the breadth of the stall, and closed at the ends, should be placed at the head of each stall, its under side pierced with small holes, or, what will be better, a slit or small aperture stretching nearly across its whole length. This pipe should com- municate with a cistern or reservoir, placed at a level considerably above that of the stalls. The coarse litter and solid manure (when the stalls are wished to be thoroughly cleaned, and the manure in the pipes to be flushed down into the reservoir) being removed, the communication between the pipe at the head of the stall and water cistern is opened, and a thin but powerful stream of water is projected down the inclined plane of the stalls, carrying along with it all impurities, and the man- ure in the pipes, to the reservoir. If the stream is continued for any length of time, to sweeten the stalls, the accession of water to the contents of the reservoir might deteriorate the manure. To pro- vide a remedy for this, let a pipe or drain be con- 90 VENTILATION APPLIED TO nected with the drain running before the stalls, leading to a cesspool independent of the reservoir. This pipe should be provided with a stop-crane ; or other means for shutting off communication, the same should be applied to that leading to the re- servoir. By shutting the stop-crane leading to the reservoir, and opening that of the cesspool, the water will run thereto, and vice versa. Fig 1. Fig. 1. illustrates the incline of the stall and position of drains : b b is the stall, c the floor of the stable, here represented as formed of small stones ; a the section of the drain or pipe running before the stalls ; d the water pipe ; e the small pipe leading from the water cistern to supply the pipe d. We should recommend the cistern containing the water to be placed at the roof of the building. If the source from which the water is to be obtained be at a lower level than that of the roof, the water may be pumped up to the cistern from a supply below. And we would here draw the attention of farmers to the important means for preventing fires thus put in their possession by adopting such a plan as here recommended. For, by leading pipes from the cistern to convenient places in the walls in the in- teriors of buildings, and finishing them there with AGEICULTUEAL STEUCTUEES. 91 screw-cocks, to which leathern or gutta percha hose may be attached when necessary, a powerful stream of water may be directed to any part of the interior required. For application to the exterior, pipes should be led to little square wells cut in the ground at the sides and ends of the building : these should be somewhere about two feet square, and one foot deep and lined with bricks the end of the pipe projecting up the centre of this well, and provided with a screw-cock, to which the hose may be attached. Trap-doors made of iron or wood may be used to cover these wells when not in use. Any part of the building may be com- manded with pipes leading from these. It will be evident, also, that such a plan will be available for the cleaning of windows, &c. without and within also the floor. For these latter purposes, the nozzle of the hose should be very small, about three-eights of an inch diameter. Moreover, should the building so furnished with a high level cistern beneartheAowse and other offices, and at a higher level than these, the supply of water might be made available for the extinguishing of fires there. The annexed is a diagram illustra- tive of the mode of managing the flow of water through the exuvias pipes: a is the pipe running before ~ the stalls, leading into the pipe 1 5, which goes 92 VENTILATION APPLIED TO to the liquid manure reservoir ; there is a stop- crane at c ; dd is a pipe leading to the cesspool or water drain. When the valuable exuviae are all washed into the reservoir, the stop-crane c is shut, and that of e opened ; the water from the stalls, debarred from flowing to the reservoir, turns off to the cesspool through the pipe d d. In ventilating stables, cow-houses, &c., the supply of air will require to be of larger amount than for buildings where human beings are to assemble. In Chapter II. we have shown that four cubic feet of air is a fair allowance for each individual per minute; now, for horses and cows, it may be assumed that three times as much will be required. The rule, then, for finding the area of foul air ventiducts will be as follows. Multiply the number of horses the stable is to contain by 12, and divide this pro- duct by 43 times the square root of the height of the tubes in feet, (that is from the ceiling to the floor,) and the quotient is the area of the ventilation tube or tubes in feet. The fresh air should be admitted by apertures in the walls, and led by tight channels to pits or wells made in the floor, between the outer edge of the stalls and the out- side wall. Supposing the size of apertures for fresh air to be six inches square ; the pits in the floor should be of depth sufficient that, when the lower edge of the ventiduct is flush with the bot- tom, the upper edge of the ventiduct should be two AGRICULTURAL STRUCTURES. 93 inches from the floor : this will make the depth of the pits 8 inches ; their breadth may be 15 inches and length 2 feet. They should be covered with gratings. The apertures for fresh air should be made below each window ; if possible, the area should be divided to admit of this. Supposing there were six windows, and the area of the fresh air ventiducts required to be six square feet, six open- ings should be made, each one foot square in area of aperture. It would be better to have the air diffused as much as possible. This might be effected by having a pit made the whole length of the stable, in the middle of the floor, and covered with a grating, below which perforated zinc should be placed. All the apertures should have valves fixed on the outside, to regulate the admission of the air. In leading the ventiducts for the foul air, care should be taken to have these properly arranged. In most cases there is a loft above the range of stables, in which hay is kept : it might be awkward to pass the ventiducts through the space ; but if the room taken up by them is of no great consideration, we would recommend them to be carried right through the space to the external roof. A ventiduct should be placed in the ceiling in such case, above the stall, as near as may be in the centre, so that the air will at once be led off. The ventiducts should have valves to regulate the admission of the air, and be regularly finished at the top. In cases where the ventiducts 94 VENTILATION APPLIED TO cannot be led through the space at once to the ex- ternal roof, air channels must be made in the wall at the head of each stall, or at the ceiling above the windows opposite the stall. These should have valves at their apertures in the interior ; and, at the place where they open into the external atmos- phere, they should be provided with tubes carried some eighteen inches above the level of the wall, and finished regularly at top. In all cases where it can be done, we would recommend the ventiducts to be continued from the inner ceilings through the space, and out to the external atmosphere, taking care to continue them at least twelve inches above the level or ridge of the roof. In stables well sup- plied with means for admitting fresh and with- drawing foul air, the doors and other openings may be as tight as possible no air entering through them yet the interior will smell sweat and clean. From the suggestions we have given relative to the ventilation of public buildings, the practical man will have no difficulty in applying the principles to stables, always remembering to have a much larger supply of fresh air secured, than for public buildings, for human beings. There is a variety of agricultural structures to which the principles of ventilation we have practi- cally illustrated may be beneficially adapted. In order to enable the reader to apply these, we will give one or two examples. AGRICULTURAL STRUCTURES. 95 And, first, as to drying-houses for grain, wool, seed, &c. As no drying-house can be thoroughly in- dependent, in its action, of all external circumstances, without the application of heating apparatus, we will suppose, for sake of the arrangement we have adopted, that the reader has, in Chapter V., re- ceived a knowledge of the rationale of the process of warming, by the different modes explained. In the construction of drying-houses, two things should be borne in mind : first, the nature of the principles which regulate the process of drying ; secondly, the mode of arranging the substances to be acted upon, so as to present them in the most favour- able position to the action of the drying agent. All drying consists in applying such a degree of heat as will convert the moisture contained in the substances to be operated upon into vapour, and in taking advantage of the affinity that air has for moisture. This affinity, acting more or less strong- ly at all times, is greatly increased by raising the temperature of the air, thereby producing an effect equivalent to a diminution of atmospheric pressure on the exterior surface of the articles operated upon, which very much facilitates the removal of the inherent moisture. It should be remembered, how- ever, " that though the air has affinity for moisture, it can absorb it only in the state of vapour ; and therefore, as much heat as will convert all the water in the goods into vapour, will still be required besides 96 VENTILATION APPLIED TO that necessary to heat the air, the action of the air's affinity being chiefly effectual in accelerating the pro- cess of drying. Currents of air passing through or between the articles to be dried materially assist the drying, inasmuch as each succeeding volume of air passed receives its quota of moisture, which it carries off. As it is evident that dry air will be most effectual, care should be taken not to admit the same quantity of damp as of dry air. In cases where the air is damp, it should be admitted spar- ingly, and the temperature increased, " otherwise," says Tredgold, " there will be a want of heat. For whatever air you admit carries off heat in pro- portion to the quantity ; and if it be already satu- rated with moisture, it carries off less water : but you give it the power of absorbing a greater quan- tity by raising its temperature." Having thus briefly shown the principles of dry- ing, without at all entering into the somewhat abstruse points of the question, we will proceed to the practical details of the construction of drying- houses, in the explanation of which will be found the modes recommended to attain the second desi- deratum we have previously mentioned namely, the proper disposition of the materials to be dried. Houses for drying grain, &c., can in some small measure be made effectual without the aid of heat- ing apparatus ; but the agriculturist may rest as- sured that it will be most conducive to his interests AGRICULTURAL STRUCTURES. 97 in constructing a drying-house to adapt thereto a well-arranged and efficient contrivance for heating. With it he will find that, in course of time, the extra outlay will be amply repaid, and his addi- tional trouble fully compensated by his indepen- dence of all external circumstances, such as damp- ness, closeness, &c. of the atmosphere. In making provisions for the withdrawal of air from the interior of drying-houses, the size of apertures will be found by the following. By a series of expe- riments, which it is here unnecessary to give, Tred- gold found, that for each 270 feet of surface of pipe, (steam or hot water, see Chapter V.,) 775 cubic feet of air w r ere to be passed through the drying- house. The rule he gives is this : Divide 7.75 by the square root of the height of the ventilating tube in feet ; the area will be the amount of area required for the ventiducts. " The height must be measured from the centre of the hot chamber (con- taining the pipes) to the aperture where the steam and hot air go out into the atmosphere. Thus, if the height be 25 feet, the square root of 25 is 5, and 7.75, divided by 5, gives 1.55 square for each 270 feet of pipe surface." Thus, it will be seen that for every 270 feet of surface of pipe, one and a half feet of area for air ventiducts should be allowed. The apertures for the admission of fresh air should be of the same size, if admitted by pipes ; but it will be better in all cases, in order to prevent 98 VENTILATION APPLIED TO too sudden an influx of air, to make them at least one-third larger. The supply of air should be under efficient control; valves should be used to regulate its admission : these should also be sup- plied to the egress ventiducts at the top. As the amount of air admitted should be proportionate to that sent out by the egress ventiducts, the valves in both them and the ingress should be opened to the same extent. Thus, when the egress venti- ducts are opened one-half; the ingress ventiducts should also be opened one-half; whatever may be their respective areas, the proportion should inva- riably be maintained. The annexed diagram will explain this : q, a is the wall ; b the aperture for supplying the interior with air; c the ventiduct for leading off the vapour and heated air, supplied with avalveJ; the cord ee', passing over pulleys, (not shown in the diagram,) leads from the valve d to the " dam- per-valve"/, suspended in a frame, close to the inside of the opening. An inspection of the figure will show how, when the valve d is opened by pulling down the cord e 7 , the valve f passes past the aperture b in a corresponding proportion. If the aperture b is flush with the ground, a space must be made, into which the AGRICULTURAL STRUCTURES. valve f can descend. To know the 'degree of opening of the valves, an index, such as described in Chapter II., may be attached to the wall, near d, and a pointer fastened to the cord, so adjusted that, when the valves are shut, it shall point to the Fig. 3. 100 VENTILATION APPLIED TO word shut ;" the words, open," " half," and " three-quarters," being at their respective places on the index. We will now explain Figs. 3 and 4, which con- tain a section and plan of the general arrange- ments of a drying-house for grain premising, first, that the reader has understood the reasons we have given for recommending the system of heating by hot-water pipes (which will be found in Chap. V.) Fig. 3 is a longitudinal vertical section of a drying house ; a a the walls, b & the ground on which the house is built, c c a place excavated in front of the house, e the steps by which access is gained to the floor of c c, d the furnace and boiler of the heating apparatus, /the gang- way stretching across the excavation to the door g; h h a false flooring, composed of small beams, two inches thick and four deep ; having an inter- val or space of two inches between each, through which the heat from the pipes Jc k as- cends; these pipes tra- verse the space between the floor of the building and the false flooring h h; I is the feed cistern (alluded AGRICULTURAL STRUCTURES. 101 to in Chap. V.) Fig. 4 is a plan of the building, the same letters referring to it: k 7c is the ascend- ing pipe, curved as seen, and should be supported and kept clear of the ground by non-conducting supports say bricks or blocks of wood ; the line of pipes should be flush with, or a little above the level of the bottom lines of the fresh-air ventiducts; the curves in the pipes should not be less than two inches radius that is, part of a circle four inches diameter sharp curves or turnings reducing the flow of the water. This ascending pipe should be continued to within sixteen or eighteen inches of the surface of the water in the feed-cistern ?, shown in Fig. 3 ; m n, the return pipe, should be covered with non-conducting material. The arrangements of every drying-house will, of course, vary accord- ing to local circumstances ; but the two figures given will be sufficient to enable any one to put the plans into practice in almost any situation. As the rules for finding the apertures of the ven- tiducts depend upon the knowledge of the quan- tity of pipe in the interior, we will now explain the rules for finding the required surface for heat- ing the air supplied to the interior. The temperature of the external air that supplies the ventilation dif- fers from that of the heated, supplied to the interior. The difference between them must be ascertained. Mr Tredgold is of opinion that the difference will never be more than 50. The mean temperature of 102 VENTILATION APPLIED TO the pipe must also be taken into account; as likewise that at which the air in the interior is proposed to be maintained. Supposing the former to be 140, and the latter 100, the rule will stand as follows : " Multiply the number of cubic feet per minute, of air to be heated, to supply the ventilation and loss of heat, by the difference between the tempe- rature the house is to be kept at, and of the external air in degrees of Fahrenheit (in the case we have supposed 50,) and divide the product by 2*1 times the difference between the mean temperature of the pipes (140,) and the temperature of the house (100,) this quotient will give the surface of pipe required." In a pipe one inch in diameter, it takes 3'28 feet to give one foot of surface. As there is a considerable loss of heat through win- dows and doors in the former it is " simply pro- portional to the surface of glass exposed to the external air" we would recommend as few win- dows as possible to be made in drying-houses, and the doors to be made double. Mr Tredgold gives the following rule, by which the amount of cubic feet of air to be warmed per minute is found : " To the length in feet, multiplied by half the greatest vertical height in feet, add one and a half times the whole area of glass, and also eleven times the number of doors ; the sum will be the number of cubic feet to be heated in a minute from the temperature of the external air." This quantity AGEICULTURAL STRUCTURES. 103 found is to be used in the rule above for finding the surface of pipe. In all provisions for heating, it is better to err in excess than deficit. The cur- rent of air through the interior should not be too great, as the obvious effect of great -velocity will be the drying of the exterior of the goods, while the dampness will still remain in the interior. To insure the current in every part of the house, the area of the ventilators in the top should be distri- buted pretty equally over the roof. Thus, if the area required is six feet, there should be six venti- lators of one square foot each. The disposition of the grain to be dried is matter of no small import- ance ; the sheaves as taken from the field are too thick, and should be separated. In Fig. 3, the small squares i i represent sections of wooden beams, stretched across the breadth of the house, and rest- ing at the ends on projecting brackets, fastened on the walls. If these are placed two feet or so apart, room will be given for spreading out the grain, putting up a few beams, laying in the grain, and thus proceeding till he gets to the last near to the door. When filled, the door should be carefully closed, and the heat of the pipes kept up to the desired maximum ; this can be ascertained by a thermometer placed on one of the pipes, below the false flooring. After the grain is extracted from the straw and is required to be dried, flat shallow cast-iron or tin dishes, punched with holes, 104 VENTILATION APPLIED TO should be laid on the false flooring, and the grain laid in these; the heated air will pass through the apertures in the dishes. We trust that the hope expressed by Mr Tredgold will be realised, that " in many districts the use of artificial heat will increase, and the loss of much valuable grain be prevented. Besides," continues the same author, " with the knowledge that he can save his corn in good condition in a full season, the farmer will have a mind more at ease: he becomes secure of that which, in the ordinary course, is very frequently injured, and sometimes altogether lost. He may also turn the same contrivances to advantage in a wet hay harvest, and temporary erections will soon be changed for more permanent ones. The cer- tainty of artificial heat will be to the farmer as important as the certainty of power is to the sailor ; and these two classes of men, who have hitherto depended more than any other on seasons, will both receive great benefit by the application of heat. It is not farmers alone that will be benefited by drying corn artificially in backward and wet sea- sons ; for, in such cases, the whole population will feel the benefit of this plan. Unsound grain makes very indifferent bread, doctor it as you like ; and the evil is too frequently a general one." In arranging wool in a drying-house, instead of laying the fleeces on the beams in the manner pre- viously described for grain, they may be suspended AGRICULTUEAL STRUCTURES. 105 from the beams by small pieces of cord ; the great desideratum being to expose as much of the surface to the action of the current of heated air as possible. For drying the various kinds of seed, the plan re- commended namely, to use flat shallow dishes with perforated holes will be the best. The bodies should be shifted now and then, by means of the hand or a wooden shovel. In ar- i > ranging peats, turf, &c. for drying, they should be plac- ed two by two on the beams leaning against one another, a a are the peats ; b b the beams on which they rest ; the dotted lines show the course of the upward current. Temporary structures for drying may be easily raised. The simplest mode of doing so will be as follows : Mark out the size of the house, and make an ex- cavation twelve inches deep, making the floor hard and dense as possible, by ram- ming. At each corner, drive in tightly square beams, of height sufficient for the ele- vation of the house ; connect these firmly together by simple tie-beams. The an- nexed figures will amply illustrate the mode of construction b b the beams 106 VENTILATION APPLIED TO at the corners. The mode of forming the roof is thus : Make a square box a for the air to escape through ; pass from the corners of this, when fastened in the centre of the roof, beams c c c c to the corners of body of the structure, thus supporting the box a above the level of the head of the beams b' 5, as seen in the upper figure. The spaces between the supports c c are covered in by a tarpaulin, all except the opening of the ventiduct a. This tarpaulin should be con- tinued down the sides and ends of the building at least one foot, so as to insure as much tightness as possible. The sides may be closed in by clap- boards, overlapping one another ; or more cheaply, and as efficiently for a temporary structure, by tar- paulin nailed tightly to the beams b b. But whether boards or tarpaulin be used, care should be taken to carry out the folio wing recommendation. To supply fresh air, a space, as i i in the upper figure, is to be left all round on each side and end ; e e is the line of the ground ;/the clap-boards this space can be left by beginning the boarding twelve inches or so from the ground, or continuing the tarpaulin down to within that distance of the ground. The upper figure is a side elevation, and the lower a plan of the roof of the structure. A more simple plan for the roof might be made, by adopting a large sheet, stretched flat across the roof, with a hole or holes in the centre for the egress of air. AGRICULTURAL STRUCTURES. 107 In windy weather such a house will be very effi- cient in drying wet hay, &c. ; but simple heating apparatus may be adopted with considerable facility, which will render its use available in all weathers. For the sake of arrangement, we will here give a description of a very cheap and portable heating apparatus, the action of which depends upon the circulation of hot water in tubes, explained in Chapter V. Fig. 1 is a section of the apparatus. Procure a large iron Fi tube a a, open at both ends ; to this fit another tube in the inside, the mouth b of which is larger in diameter than the other end ; let the difference between the diameter at the largest end and that of the external tube be two inches, thus leaving a space of one inch all round ; the small end should be one third of the diameter of the large. The ends of the tubes should be joined together by plates of iron, well soldered with brass, so as to make a perfectly tight communication running right through the external tube a a. The tube thus fitted should rest upon small horses or trusses/// in the large end Z> a small grating should be inserted, in which charcoal, peat, or common coal may be burned ; and at the small end, a tube or chimney may be attached leading upwards for 108 VENTILATION APPLIED TO a few feet. This will increase the draught, to regu- late which a valve may be inserted. Now, sup- posing the space between the two tubes to be filled with water, and the fire at b kindled, it will be easily seen how the heated air, impinging upon the interior surface of the pipe in its progress through it, will soon heat the water contained be- tween the space of the two tubes. Here, then, is a supply by which a congerie of pipes in the interior of the drying-house may be supplied. As the ascending currents of heated water should be taken advantage of, in promoting the circulation through the pipes, the main tube a a, or " furnace boiler," should be situated at a lower level than the floor of the drying-house. This may be simply effected by making an excavation, as shown in the figure, at an end of the house. To the upper side of the "boiler" near the house, Fig. 2. attach a pipe, say one inch diameter at e, com- municating with the space between the two tubes ; lead this pipe up to the diying-house, as shown in Fig. 1, and cause it to describe a series of curves, as seen in Fig. 2; and finally lead it to the middle of a tank of water which will be the feed-cistern ; AGEICULTUEAL STRUCTURES. 109 bring from the bottom of this cistern a pipe Ji, as seen in the dotted line on Fig. 2, and attach it to the under side of the furnace boiler, as shown at c in Fig. 1 . There will thus be a continual current of hot water proceeding from the boiler through all the convolu- tions of the pipe e e to the feed-cistern, and through the descending pipe h to the furnace boiler, again to be heated the amount of evaporation escaping through a small pipe in the cover of the feed-cis- tern. The internal tube of the boiler should be made of thin copper, which will last longest, and communicate the heat of the fire quicker than if made of iron. The tube of the boiler should be wrapped round with felt, or other non-conducting material, as also the parts leading from the house. This will prevent the loss of heat. The whole apparatus can be made portable very simply by attaching screw couplings to the pipe where it en- ters the upper and lower sides of the tube, as at e and A, and at the places where they enter the feed-cis- tern. By unloosing these, the tube will be separated from the boiler and feed-cistern, and conveyed where necessary the congerie of pipes in the interior being lifted in one piece ; or even this may be detached one piece from another, by screw couplings. The congerie of pipes should, when in use, be kept up from the floor, in the manner described for grain drying-houses. The hay, &c., to be dried in the temporary house we have described, may be placed 110 VENTILATION APPLIED TO on hurdles easily constructed of pieces of scant- ling. The principles of ventilation should be applied to other agricultural structures not yet noticed. Thus swine-cots, hen-houses, &c. can be efficiently constructed, so as to combine with neatness and cheapness the amount of comfort necessary for the animal. Dairies cannot be too well supplied with pure ffesh air ; to attain which, the sites fixed upon should not be in the neighbourhood of aught that contaminates the supply. The an- nexed figure will enable the agri- culturist to apply the principles we have elucidated : a c the walls; 6 the ventiduct, for al- lowing the air to pass out ; c a table, nearly the length of the apartment the inside of which is supplied with fresh air through the ventiducts d d, and the sides and ends of which are perforated. The shelves e e are supplied with air through the venti- ducts ; as seen, these stretch across the whole length of the room, so that the air may have access to the whole range. The shelves may be made of light frame-work with diamond-shaped apertures. Cast- iron frames would in every case be preferable, FT AGEICULTURAL STRUCTURES. Ill light, cool, and easily cleaned. Instead of using the top of the table c to place dishes upon, the in- side may be fitted up with perforated shelves, the top lifting up as a lid ; or side-doors may be made : these should fit very close and tight. We trust that, in our remarks, we have very plainly elucidated and explained the principles upon the application of which the heating and ventilating of agricultural structures depend, and that the practical fanner will have no difficulty in applying these, in any case where they may be considered necessary. CHAPTEE V. WARMING OF BUILDINGS CONSTRUCTION OF FIREPLACES SMOKY CHIMNEYS. " Dry be your house but airy, more than warm." ABMSTRONG. THOUGH much consideration has been given to the nature of heat, still nothing has yet been received as a true explanation of the phenomena which it presents ; and among scientific men its real nature is still a subject of dispute. As it is foreign to the subject of this treatise to enter into a long discus- sion of the different theories promulgated, we will content ourselves with explaining its effects, and the simplest mode of applying them to the warming of public and private apartments. The two methods by which warm bodies afford heat are "radiation" and "conduction," or by " contact." " Kadiation signifies the rapid emission of heat and its passage from one body to another, in the same manner as rays of heat pass from the sun to the earth." It is radiant heat we receive WARMING OF BUILDINGS. 113 from a fire. " Conduction signifies the slow and direct communication of heat from any warm object, to another in actual contact with it." A stove affords heat principally by conduction, as do also pipes containing steam or hot water. To assist the reader in forming an idea of the effects of heat, as above explained, we here give some of the " Memo- randa" compiled by Dr Eeid. " Different bodies vary much in their power of radiation : those with rough and porous surfaces radiate well. Bodies that radiate well when hot, absorb it quickly when cold ; as good radiators are also good absorbers of heat. Polished metals are bad radiators of heat, bad absorbers of radiant heat, but powerful reflec- tors, throwing back a large portion of any radiant heat that falls upon them. Metals are good con- ductors of heat, taking it rapidly from any object warmer than those with which they may be in contact, and evolving it equally to those that are colder, and hi contact with them. Glass, brick, porous solids as charcoal, fur, cotton, and wool are bad conductors of heat. Bad conductors are used for surrounding materials to be kept warm or cold, that heat may not escape from them or enter to them. The most powerful combination, for giv- ing or acquiring heat, is formed where the material is composed of metal, that the conductors may be good; and the surface non-metallic, but porous, soft, or painted, that the absorption or radiation H 114 WAEMING OF BUILDINGS, may be powerful. Again, in the most perfect ar- rangement for retaining heat, the substance should be made of a non-conducting material, and the surface of a brilliantly polished film of metal, that it may neither conduct nor radiate well, but be powerful in reflecting." In cases where the heat is communicated between substances at a greater or less distance from each other, radiation is the term applied. When the " heat is diffused by means of the air which, being warmed by contact, is expanded and put in motion, and communicates the heat it receives to the solid bodies in the room then the term conduction is applied." There is a considerable difference, in the gene- rality of cases, between the heat communicated by radiation and that by conduction. By the latter, air may be too much heated, so as to burn, as the expression goes, its vital humidity, by which it is made dry and unpleasant : moreover, if too highly heated, it increases the effect of the warm air to absorb moisture. Hence, a party with wet clothes, in entering an apartment filled with overheated air, is in great danger of catching cold ; as the evapora- tion of moisture from his damp clothes, earned on by the warm air absorbing it, the abstraction of heat from his body will be considerable. That cold is produced by evaporation is amply proved by the beautiful and decided experiment of Professor CONSTEUCTION OF FIREPLACES, ETC. 115 Leslie, who actually froze water by absorbing the vapour by means of sulphuric acid as it rose from the water. The experiment may be familiarly tried, by waving the arm swiftly in the air, taking care that its surface is wet ; or, still more convin- cingly, by pouring ether on the back of the hand. In the latter case, the evaporation being extremely rapid, the degree of cold produced is absolutely pain- ful. An apartment warmed by radiant heat is, to a very considerable extent, free from these disad- vantages ; as the air is cooler than the objects receiv- ing heat from the fire. " The rays of a fire produce no more vapour from moist bodies than they supply with heat ; and therefore they produce no cold when unaided by the affinity of warm and dry air. Moisten the bulb of a thermometer, and expose it to the action of warm dry air, and it will sink down several degrees ; but when moistened and exposed to the rays of a fire, it rises. A person warmed by radiant heat is always unequally warmed ; and if the introduction of cold air be injudiciously man- aged, he may literally burn on one side and starve at the other." It is evident that large spaces cannot be warmed by radiant heat equably and effectually ; for, in the use of a large surface of open fire, the heat near it would be insupportable ; while, far away, the in- fluence would scarcely be perceptible. To increase the number of fireplaces would be as difficult, and 116 WAKMING OF BUILDINGS, far more dangerous inasmuch as the liability to fire would be increased, besides the expense of maintaining such an expenditure of fuel, and the creation of dust, ashes,' &c. For the purpose, then, of heating large spaces, the principle of warming the air, supplied by conduction, has been adopted ; and it will be our next task to show the different modes promulgated and earned into effect, as well as to explain their mode of action. The plans hitherto in use for heating large spaces are as follows : Hot stoves or furnaces, steam and hot water. In the first, plates of metal or masses of brick or stone, or flues, are heated in, or by a furnace ; and the air to be heated is caused to impinge upon, or pass through these, thus imparting to it a degree of heat which, it is evi- dent, cannot be controlled or regulated as required. The oldest method of heating by such means is what is termed, " the cockle" the most scientific modification of which was made by Mr Strutt, of Derby, so early as 1772. Its principle depended upon keeping the air to be heated, in its passage over and through brick flues, at such a distance from the heating power that the temperature of the air could not exceed a certain degree. To obtain this desideratum in such contrivances is very difficult ; and the structure required cumbrous, and clumsy in size and shape, and expensive to be kept in full operation. Air, when heated to a degree CONSTRUCTION OF FIKEPLACES, ETC. 117 above 212, or the boiling point, is burnt or desic- cated that is, deprived of its inherent moisture consequently, causing it to have an unhealthy action on the bodies of those subjected to its influ- ence. Heated air, then, should never be above this point ; to attain this desideratum is, with stoves, almost an impossibility. Excluding, then, from our notice, the infinity of stoves vaunted as " perfect and complete in every department," we will only notice those which may be adopted with- out fear of producing deleterious effects. The most important of these, and the one most widely known, is the Arnott Stove, so called from the learned inventor. The most striking peculiarity of this stove is, that it " combines extreme economy of fuel with great facility of attendance ;" such arising from two causes the large amount of heat which is detained by the stove, and the compara- tively small quantity of air which is removed by combustion." This contrivance being made by so many manufacturers, it is so generally known that it is needless to take up space by giving a detailed description. The principle, however, may be noticed. A large outer case is provided, in the interior of which there is a small fire, the products of combustion of which proceed to the chimney by a series of turns, the air in the interior surrounding these being heated by contact with them. It is to be regretted that many so-called Arnott stoves are 118 WAEMING OF BUILDINGS, by no means made on the correct principles made public in a very generous manner by the inventor. The Porcelain Stove, recommended by Dr Eeid, is another low temperature stove. They are much used in Sweden, France, Russia, and other countries. The plan may be described as an oblong chamber, some ten or twelve feet high, at the lower end of which the fuel is placed. The flue at the top is made of a square tube, leading upwards a short distance, turning to the right, along in a horizontal direction far enough to clear the side of the main chamber ; then bent down- wards, and, proceeding to the bottom, turning again, running parallel to the floor to the corner of the chamber ; bending upwards, and continuing so till reaching a height above the top of the main cham- ber, equal to the pipe as it first begins; then, stretch- ing across the breadth of the head of the main chamber, and down to the opposite side along the floor, and up, where it is continued to its place of exit. The inside chamber and tubes are all covered by an external case, having apertures at its upper part to admit the heated air to the apart- ment in which it is placed. They are quite diffe- rent in their action from the hot German stove, as understood in this country ; and Dr Reid says, that, from his own personal experience in examining them, he is enabled to say that he knows no stove that produces a more mild, genial, and equal tern- CONSTRUCTION OF FIREPLACES, ETC. 119 perature. As the tendency of hot air from all stoves is upwards, to insure their full effect, they should be placed at a lower level than the apart- ment they are intended to heat. In heating large apartments, we would by no means recommend the adoption of stoves ; we think we have said enough to prove that, expensive in construction and operation, they are not by any means controllable in their action. We will pro- ceed, then, to explain the two other modes, which in the generality of cases are now adopted these are steam and hot water. These, as used for the purposes of heating, are caused to circulate through a congerie of pipes, which heat the air surrounding them, by a combination of the two effects of heat, radiation and conduction principally, however, by the latter. In the year 1745, Colonel William Cook first suggested the idea of employing the heat of steam as a means for warming air. The first patent for this plan was granted in 1791 to John Hoyle of Halifax. His plan was, conveying to the places to be warmed steam pipes, passing these into, round, or through them " the pipes, being first raised to their highest elevation, and then descending with a gentle declivity to a cistern for the condensed steam." In the application of steam to heating purposes, the peculiarities are the distance to which it may be led from the place where it is generated, 120 WARMING OF BUILDINGS, the uniformity of temperature at which it can he sustained, and the facility with which it can he led in any direction upwards, downwards, or laterally. Moreover, the fire-place of the hoiler may be made in any place convenient, however far separated from the building to be heated. Thus, cases have been known when the distance from the boiler to the extreme end of pipe has been 800 feet. The steam to supply the pipes is generated in a boiler, and sent through the range of pipes, arranged in num- ber and situation as required the water of conden- sation either returning to the boiler or led to a convenient place. The hot-water system is divided into two classes, " low " and " high " temperature the former consisting of a congerie of pipes communicating with a boiler or receptacle placed at a lower level, to which the heat is applied. A receptable at the highest parts or extremity of the pipes is placed, into which the water caused by the expansion flows, and from which it returns again by pipes to the boiler, to be heated anew. Thus a constant circulation is kept up, and, the receptacle or cistern being open to the atmosphere, a higher temperature than 212 cannot possibly be obtained. In the " high " temperature, the pipes are hermetically sealed after the water is put in, allowing ample space for expansion ; and by continuing the heat of the fire, a degree of heat may be obtained far above CONSTEUCTION OF FIREPLACES, ETC. 121 212. It will be perceived, however, that if air comes in contact with the metal pipes, it will be as much desiccated or burnt as by the common highly- heated stoves so justly complained of " to avoid the deleterious effects of which," says Mr Bramah, " has been the principal aim in the application of the process now under consideration." The mode of heating by hot water was invented and applied in the last century in France. The Marquis de Chabannes strongly advocated it some thirty years ago ; he says, " There cannot be a more perfect idea of the whole operation of the new patent water calorif ere, than by comparing its boiler to the human heart, and the tubes through which the water passes to the blood-vessels in the human body. In the water calorif eres, the water is in constant movement as the blood in the veins ; it goes out of it by an upper tube, as the blood by a valve in the heart. It circulates through the house, ascends or descends at will, and returns into the boiler at the bottom, to charge itself again with fresh caloric, as the blood ascends, descends, and passes again into the lungs to regain a new portion of oxygen, and recommence constantly the same function of carrying heat to the extremity of the body." The annexed figure illustrates the rationale of this process, where a represents the boiler, b the feed-cistern, c c the ascending or hot pipe, d d the 122 WARMING OF BUILDINGS, descending or supply pipe. The water from the feed-cistern des- cends the pipe d d, and fills the interior of the boiler a ; by the action of the fire the temperature of the water is raised, and, according to the laws which regulate the motions of hot fluids, it flows up the pipe c c to the cistern b. A regular and unintermitting descent of cold water down the pipe e?, and hot water up the pipe c c, as indicated by the arrows, goes on until the temperature of the whole body of water is the same. Properly speaking, this never happens, as a portion of heat is abstracted from the pipe c c by radiation and contact : the motion may be said to be continual, so long as the fire is properly supported. The feed-cistern is supplied with cold water by a pipe e, and a waste-pipe f is provided to allow the escape of the water of expansion. This, being open to the atmosphere, also allows of the escape of any vapour, so that the heat never can exceed that of 212. If the feed-cistern is at a considerable elevation above the boiler, as the pressure of the water therein is greater than ordinary, the boiling will vary in proportion to the height. Thus, in an apparatus in which the boiler is 60 feet below the cistern, the CONSTRUCTION OF FIREPLACES, ETC. 123 boiling point is 270, instead of 212. To prevent all loss of heat from parts not required to give out heat, the boiler, cistern, and part of the pipes necessary, should be covered with non-conducting materials. The mode of applying these we will describe hereafter. The cause of the circulation of the hot water in pipes is produced by the " un- equal density of the fluid, arising from the difference of temperature in the ascending and descending columns of water connected with the heating reser- voir ; and its velocity is governed by the height of the columns." In the " high temperature " system there is no communication whatever with the ex- ternal atmosphere, the tubes being hermetically sealed after being filled with water. The feed- cistern is thus dispensed with, and an expansion tube substituted in its place, at the highest part of the range of pipes : the size of this expansion tube is one-fifth of the contents of the whole piping. As to the comparative merits of the two systems heating by steam, and by hot water we do not consider it necessary to enter into a long discussion. But in the generality of cases, where large spaces are to be heated, we would recommend the adoption of the latter mode. " As contrasted with steam heat," says Mr Bramah, " it may be remarked that the extreme simplicity of the hot-water apparatus, and its freedom from those casualties which are incident to an accumulated temperature in steam, 124 WAEMING OF BUILDINGS, renders it a desirable means for adoption in domestic economy; for while, on the one hand, heating by steam necessarily involves liability to accident, from the increased ratio of the force of vapour, as compared with that of its sensible heat, and which is frequently occasioned by the derange- ment either of the feeding or the safety apparatus ; on the other hand, by the substitution of hot water, this serious inconvenience is avoided: while the expenditure of the water is, in this latter mode, no greater than the quantity lost from leakage ; or the slight evaporation which can occur is limited to the effect of over-firing, by which water may be driven out of the upper part of the pipes, or from the feed-cistern of the apparatus, into the channel provided for its escape, so as to produce for a short interval a reduction in the temperature of the remaining quantity, by the immediate influx of cold water from the source to supply the deficiency thus occasioned." And the Marquis Chabannes says " Hot water is preferable to steam in many respects. Steam requires a strong fire, and to be always kept up | whereas very little fire is sufficient to keep up the heat in the water when once boil- ing, and to renew the caloric, which is continually passing through the different apparatus for spread- ing the heat : it is therefore much more economical. " For agricultural structures, steam certainly possesses the advantage of a ready means for preparing CONSTRUCTION OF FIEEPLA-CES, ETC. 125 mashes and boiling water in a very short time. But to set against this, the steam often riot being readily raised when required, and from the time taken up in doing so, to keep steam apparatus in continual action involves a very considerable degree of attention and outlay of fuel ; while in that of the hot water, a very small fire will keep up a considerable degree of heat for any length of time. For public buildings, hot water should in all cases be employed ; but in some districts, where fuel is plentiful, and parties may be inclined to fit up steam apparatus, we consider it best to explain some of the minutise of construction of such, as well as of hot-water apparatus. Steam Apparatus Construction Boilers. We do not consider it at all necessary here to enter into the minor details of construction, such being- known to the mechanics who will be employed in the manufacture of the apparatus, but merely to give general hints, to enable the parties fitting up such to see that the conditions required to make it efficient are fully carried out. The shape of the boiler we would recommend is that known as " cylindrical." It is easier made than the spherical, and possesses many of its advantages. It may be made of copper, but thin iron will answer well enough. Care should be taken to have the metal, on which the flame of the fire infringes, thin ; by being so, considerable time will be saved in raising 126 WARMING OF BUILDINGS, the water to the boiling point; and it will be, moreover, more desirable, as the outer surface will not be burnt, by the intenser heat which thicker metal would require. Again, it is found that even the best conductors retard the progress of heat, if of considerable thickness. In applying the heat of the fire to the surface of a boiler, care should be taken not to increase its extension when the heat is less than 212, as it is evident that there must be a disadvantage to allow heated air or smoke to come in contact with the boiler, after its tempera- ture is reduced below that of boiling water : the smoke should quit the boiler at the temperature of the steam. The space allowed for water should be a little less, but certainly not greater, than half of its cubical contents; and the space allowed for steam should not be made greater than the cubical contents of the whole range of pipes to be supplied. Hassenfratz recommends the depth of water to be one-sixteenth of the area : this proportion is only applied to evaporating boilers. Tredgold says, that, " for producing steam, the most effect is obtained when the horizontal area of the boiler is about 21 superficial feet. The apparatus for a boiler consists of a feed-apparatus, to insure a regu- lar supply of water ; a safety-valve, to allow the steam to escape when of too high pressure ; gauge- cocks, to ascertain the height of water in the boiler; and a man-hole door, to permit of entrance to clean CONSTRUCTION OP FIREPLACES, ETC. 127 the interior." The feed apparatus is simply de- scribed : To the upper end of a long tube, entering through the top, and proceeding within a few inches (say 3 or 4) of the bottom, let a small cistern be attached : this may be most conveniently made wide at the top, and sloping down on all sides, till it attains the diameter of the pipe on which it is fastened. At the head of the pipe fix a conical valve, opening upwards ; the stalk of this should project 3 inches above, and at least 6 below, the body, which rests on the conical seat. To the side of the cistern, on a line with the length of the boiler, attach a standard, in which should oscillate a lever, the length of the short arm being half that of the long. To the short arm pass a rod or wire, working in a centre, to the upper stalk of the conical valve, to which it should be attached by a movable joint. To the long end of the arm pass a wire, down to and through a steam-tight opening in the boiler; fasten a stone float at the end of this, at such a height that the bottom line should correspond with the proper line of the level of the water, when the boiler is filled to its proper height. It is easily seen how that, when the water is eva- porated, its level will sink, the float will descend with it, pull down its wire, and by that means depress the long end of the lever thus raising the short, and, through the connecting wires, the conical valve out of its seat, allowing the water to pass down 128 . WARMING OF BUILDINGS, the pipe. The cistern should be supplied with water through a pipe, the quantity of water flow- ing through which should be regulated with a ball- cock. A waste-pipe should also be provided, to take off any surplus water. In constructing this feed-apparatus, it is of the highest importance to make the tube, or rather the elevation of the cis- tern, sufficiently high, to counterbalance the pres- sure of the steam in the boiler. On a rough calculation, a pressure of steam, 15 Ib. to the square inch, will sustain a column of water 30 feet high so, for every Ib. of pressure of steam, two feet of height should be allowed. It is better, how- ever, to err in excess than deficit ; so 2^ feet may be allowed. For supplying steam for heating pur- poses, no greater pressure should be given than 4 Ib. to the square inch. A safety-valve will be easily constructed, by inserting a conical brass- valve in the upper side of the boiler. The stem of this should project 6 inches into the interior, and 3 above the exterior of the boiler. Weights, having holes in the centre of each, can be slipped over the upper part of the stem to regulate the pressure. It will be perceived that the feed-apparatus, for- merly described, if its height is regulated exactly to the pressure required, will act as a safety-valve ; the steam forcing the water up the tube, conse- quently, in a corresponding ratio, providing more space for its increased bulk when the pressure is CONSTRUCTION OF FIEEPLACES, ETC. 129 removed. The gauge-cocks should be two in number. Provide two common stop-cranes, with pipes attach'ed : the length of one should be suffi- cient to reach the water-line, and at least one inch below it ; the other should reach a little above the level. When these pipes are passed through holes made in the upper side of the boiler, and properly fastened, the stop-cranes will be outside, a few inches above the boiler. If water comes through one, and steam through the other, all is rightly adjusted ; but if steam comes through both, there is too little water in the boiler, and the feed-pipe should be looked to. If water comes through both, there is too much of it. The man-hole door should be of sufficient size to allow a person to have free access it should be tightly fastened down with a well- secured joint. Furnaces. The peculiar construction of such will depend upon the shape of the boiler. The air should have free access to every part of the fuel which is on the grating the air supplied passing generally through slits or apertures, made between the bars on which the fuel is laid. The area of these should be much larger than that of the place at the front of the furnace, which supplies air to the ash- pit. The bars of furnaces are generally one inch wide at the top, each interstice being | or \ an inch : it is found that one square foot of aperture of these admits sufficient air to consume coal, which I -130 WARMING OF BUILDINGS, will evaporate one cubic foot of water per hour. With a very quick draught, a much less surface will suffice. The extent of surface of boiler exposed to the flame of the fire is found, in the general run of iron boilers, to be fifteen square feet, for each cubic foot of water evaporated per hour : of this surface one-third is reckoned horizontal and two-thirds vertical. The area of the chimney, to carry off the gaseous products with sufficient velocity, is of importance to be known. " From an examination of the best boilers," says Mr Scott Eussell, " it appears to us decided, that one-fifth of the area of the fire-grate, gradually diminishing to a chimney, which shall have one tenth of the area of the fire-grate, is an excellent proportion :" the standard will therefore be one-fifth, diminished at the chimney to one-tenth part of the area of the grate. " The chimney should be of the same diameter throughout its interior ; and if of 40 feet height, and one-tenth part of the area of the grate, it will give an abundant draught. If the height of the chimney be greater, then this area may be diminished as the square root of the height is increased." The space for the fire should be lined with good fire-brick, built with fire-clay, and the rest of the furnace with good well-burnt bricks. With the exception of the door, bars, and dumb-plate at the mouth of the furnace, iron should not be used in its construction. As it is of importance to confine CONSTRUCTION OF FIREPLACES, ETC. 131 the useful heat as much as possible, the boiler surface exposed to the air should have an outer case ; in the space between this and the boiler, non-conducting material should be placed or this effect may be more easily obtained by building and plastering an outer case of brickwork round the boiler. A damper should be provided at the throat of the chimney ; an excellent door, which may be opened to any extent, may be obtained by adopting the plan of a " damper valve," as given in Chapter II. Mr Tredgold recommends the fire bars to be placed sloping downwards, towards the back, and the coals to be placed only at the front when supplying the furnace. The fuel thus placed will be gradually heated, ready to enter into combustion when pushed forward by the stoker ; and a new supply of fuel should then be added, in the place of that which has been thrust forward into the fire. The gases which distil from the fuel, having to pass over the red-hot embers, which are supplied with air from the ash-pit, (through the bars,) will generally be wholly consumed in passing the throat of the chimney. Pipes. The best material for the pipes is cast- iron ; it gives off, when heated, no deleterious or un- pleasant exhalation, and is cheap, and easily fitted up. They should be black, and rough on their surfaces, in the spaces where they are to give off the heat. The diameter of pipes should never exceed six 132 WASHING OF BUILDINGS, inches, nor be less than three, where the number is considerable. " The space for steam, it should be recollected, is quadrupled by doubling the diameter of the pipe, while the quantity of surface, on which the effect of the pipes depends, is merely doubled." In cases where a large surface is required, it may be better to have two pipes. Where heat is to be given out slowly, the pipes may be made large, and filled with pebbles, broken flint, properly cleaned. " By adopting this method, the pipes would not afford heat, till the flints had absorbed their specific quantity, and this quantity would remain to be slowly given out, after the steam had ceased to flow from the boiler." It is of impor- tance to have the pipes not too thick ; they should be thick enough only to secure perfect castings. In fitting up pipes, due allowance should be made for the expansion ; if this is not attended to, the joints will inevitably leak, every time the apparatus is used. The expansion is found to be a little more than the ^th of an inch, for every 10 feet of cast- iron pipe, where the temperature is increased from the freezing point to 212. As lead pipes may be advantageously used, for leading the water of con- densation to the boiler, one-fifth of an inch for every 10 feet will be sufficient. The iron steam- pipes, in order that they may expand freely, should be supported by small rollers, moving on low brackets. The best method of joining the pipes is CONSTEUCTION OF FIREPLACES, ETC. 133 by having flat flanges at the ends of each length, with bolt-holes bored in them the holes of the one corresponding with those of the other. As an efficient and elegant substitute for this white lead and rope yarn joint, used frequently, we would recommend the flat thick rings of vulcanised India rubber : they form excellent joints, when screwed tightly between the flanges. All the pipes should have an inclination downwards to the boiler, so that the condensed water may run freely thereto. If it is wanted to make as much of the heat as possible, the condensed water may be allowed to remain till cool, and drawn off by stop-cocks, placed at intervals. These should be opened before the steam is admitted, and closed after the pipes are filled ; the air will thus be driven out. It is best in all cases to return the water at once to the boiler that is, if the boiler is placed at a lower level than the pipes. As the returning water, running down the pipes, may condense the steam in its passage through them, it is better to have a small lead or iron pipe provided, to lead the water of condensation to the boiler. As it is important to confine the heat to the pipes, in places where they are required to retain it, they should be covered with felt or cotton, well wrapped round with cord and painted white. When the steam is conveyed to a distance, under ground, a dry drain should be made, filled at the 134 WARMING OF BUILDINGS, bottom with loose materials, as broken stones ; and surrounded with dry ashes, and covered with tiles, cemented closely together to keep off the water. Boxes made of wood, and covered with the same composition, recommended for the fresh air venti- ducts, in Chapter II., and filled with dry ashes or animal charcoal, would answer still better. Proportions of Pipes. For churches and public buildings, the rule is very simple. Three things should be borne in mind, in calculating the neces- sary amount of air to be heated the loss of heat from the glass, from the ventilation, and through the chinks of the windows, doors, &c. The area of the glass exposed to the external air must be calculated ; and, when found, the following is Mr Tredgold's rule : " The quantity of cubic feet to be warmed in one minute should be equivalent to four tunes the number of people the room is intended to contain, added to eleven times the number of external windows and doors, added to one and a half times the area or feet of the glass exposed to the external air : the sum will be the quantity in cubic feet." This quantity, thus found, is to be used in the following rule, by which the surface of pipes is found : " Multiply the cubic feet per minute of air to be heated, by the difference between the temperature the room is to be kept at and that of the external air, in degrees of Fahren- heit's thermometer, and divide the product by 2.1 CONSTRUCTION OF FIEEPLACES, ETC. 135 times the difference between 200 and the tempera- ture of the room : this quotient will give the quantity of surface of cast-iron steam pipe that will be sufficient to maintain the room at the required temperature." To make this calculation, the temperature of the external air, that supplies the ventilation, is to be known at the extreme case of cold, which for the day may be taken at 30 ; but, for night, may generally be assumed at once to be at zero, as the cold is seldom more intense in this country. The temperature at which it is proposed to maintain the room, or place to be heated, at the same season of cold, is also to be settled. The mean temperature of the surface of the pipe containing the steam, at the ordinary pressure is 200. In calculating the size of pipes for churches, if the windows are double, the loss of heat from ventilation is alone to be accounted for ; " if simply air-tight, the number of them multiplied by 11 may be omitted." To ascertain the number of cubic feet cooled from the temperature of the room to that of the external air, multiply the area of the surface by 1.5, and the product will be the number of feet. Mr Tredgold gives the following, which we give as an example of the mode of proceeding in the calculations : " Let us suppose a church for 1200 people to contain 100,000 feet of space, and that the congregation is, in winter, on an average 600 ; and that there are 28 windows, 136 WARMING OF BUILDINGS, with 1000 feet of surface of glass, and that it is to be kept at 60, when the external air is 30, or 30 above the external air. The loss of heat from the glass will be 1500 cubic feet. From venti- lation of 600 people, 2400 cubic feet, and from the escape through windows, 300 in all, 4200 cubic feet to be warmed per minute : the surface of steam pipe required for this, will be 428 feet. For this he recommends pipes four inches diameter. To find the time required to heat the whole content of the church, the ventilation being stopped, divide the space in the room by the quantity of air to be heated in one minute the quotient will be the number of minutes required. Thus, in the example we have given, 100,000 divided by 4200, equal to 24 minutes the time the boiler would require to be in full action. The rules thus given may be easily applied to workshops, halls of large mansions, &c. Distribution of Pipes. This is a matter of very considerable importance, and may be carried into effect in two ways : first, by erecting a con- gerie of pipes in an apartment distinct from the building, at a lower level, through which fresh air is impelled, and driven into the church by means of machinery, or drawn in by the force of the upward current of ventilation ; secondly, by distri- buting the pipes in the interior, according to local circumstances : the latter mode we are inclined to CONSTRUCTION OF FIREPLACES, ETC. 137 recommend. Of course, in both cases, the boiler and fireplace are in an apartment at a lower level. In cases where the gratings are made in the passages, the pipes should be led to these ; indeed, a narrow grating, the whole length of the passage, under which the pipe would lie, would be advantageous. In other cases, the pipe has been led along the walls, at the head of each pew, thus affording a good supply of heat. Hollow pedestals, placed in the entrance lobby, and on each side of the pulpit stairs, supplied with steam, may be used with decided advantage, and may be made highly orna- mental. Local circumstances will vary the placing of the pipes: it is for the practical man, taking advantage of the rules and suggestions we have given him, to consider the best means of applying them, and carrying them efficiently into effect. We have been thus particular in describing heating by steam, as all the rules and calculations given are applicable in every respect to the hot- water system : the only thing different in the cal- culations is, that, in the rule given for ascertaining the surface of pipe, the mean temperature must be altered; for steam it is given as 200 for the hot-water pipes, 140 may be taken as a safe approximation. (See Chapter IV., page 102.) In the warming of dwelling-houses, where the apartments are supplied with air from the central staircase or hall, the most simple and obvious mode 138 WAKMING OF BUILDINGS, of proceeding is to have a properly constructed apparatus placed in the hall, sufficient to heat all the air supplied to the interior. A series of small pipes may be arranged in the inside of a hand- somely designed table or pedestal, with open fret- work sides; or neat pedestals, or even statues, may be connected with the hot-water boiler, which should be placed in an apartment at the basement of the building. The modes and forms by which hot-water apparatus can be made effectual, are numerous in fact, varying with the local circum- stances of the place, from the plainest form or com- bination of circular pipe, to the handsomest and most elaborate decorative design. The principle in all cases is the same, the modes in which it is employed only differing. The heat from a gas jet, or rather a well-arranged series of gas jets, may be rendered capable of keeping up the requisite degree of heat in the liquid of a small range of pipe, or pedestal. A very handsome form, in which this might be adopted, is one of the many varieties of vases. Each separate apartment, in a well- arranged structure, should be heated by a pipe passing along behind the skirting which supplies the fresh air ; or if the supply is taken, as we have noticed previously, to the centre of the room, a circular range of pipes should be taken there. In leading hot-water pipes to the various apartments, those parts not required to give out heat should be CONSTRUCTION OF FIREPLACES, ETC. 139 carefully covered with non-conducting material. A study or other apartment may be effectually heated, by leading the pipes to a handsome pedes- tal placed on the hearth, the surface of which would be gently heated by the pipes within ; or the diameter of outside case might be made greater than that of the congerie of pipes in the interior : if left open at bottom or top, a current of cold air will enter at the bottom, and, impinging upon and passing through between the congerie of pipes in the interior, it will escape at the top, with its tem- perature considerably heated. A register-valve at the top may be used to regulate the ascent, or stop it altogether the heat being then only given out by passing through the outside casing. As we have before said, the application of hot water to the heat- ing of halls, apartments, &c., large or small, can be carried into effect by a series of almost endless devices. In cases where heating rooms by pipes is not approved of, we would recommend the heat of the fireplace to be used in the manner recommended by Mr Hosking, the flues supplying the fresh air to be passed near the warm portions of brick, stone, or iron work surrounding the grate, so as to heat it before it issues into the apartment. As a very efficient mode of taking advantage of the heated surfaces surrounding fire-grates, we give the following suggestions from the work of a very old author, who wrote on the proper con- 140 WARMING OP BUILDINGS, struction of fireplaces considerably more than a hundred years ago. We give the extract as it stands in his work. The practical man will have no difficulty in taking advantage of the hints thrown out, excellent as they really are. " We suppose the whole compass of the inside of the chimney (the back part of the grate) covered with a plate of iron, brass, or copper, and behind it a void space about 4 inches deep, divided by several par- titions, which form several cavities, cells, or square tubes the first communicating with the second, the second with the third, and so on, making alto- gether, as it were, a sort of recurved canal, one of whose ends must be at the bottom and the other at top of one of the jambs, coming out into the room, so that the air can go in at the lower, and go out at the upper end of it. We may also suppose the under part of the hearth hollow, and covered with plate iron nay, and the under part of the chimney-piece likewise hollow, like a pipe, so that all the cavities behind the back, jambs, under the hearth and chimney-piece, alto- gether, make forementioned winding passage. Now, supposing this passage for the air behind the chimney, as soon as a fire is made, it will warm the whole compass of the chimney, the hol- low under the hearth, and the bottom and back of the passage under the mantel-tree, (if there is one,) and consequently the air within the hollows that , CONSTRUCTION OF FIREPLACES, ETC. 141 those surfaces shut up, and the cold air which will come at the lower entrance, will begin to grow warm in the first cavity ; then, as it comes through the second, its heat will increase ; still it will grow hotter in passing through the third, &c., so that it will come out very warm through the upper hole. As long as there is any fire in the room, there will, by this means, be a constant circulation of the air through these hollows If the outward air be brought into the cavities behind the chimney, (grate,) by carrying on a communication from the lower hole quite out of the house, the room may also be warmed sooner, as well as to better purpose, than when we only cause the air in the room to circulate : a great quantity will then go out in the same time through the upper hole, because it goes quicker, as it is always more pressed from without than from within the chamber." It will be perceived that drawing the supply of fresh air from the external atmosphere is the better mode of proceeding ; and the flow of warm air into the room may be regulated by a damper or valve placed at the entrance of the fresh-air ventiduct, where it joins the cavity behind the grate : of course, the greater the velocity of the current through the cavity, the less will the air be heated, so that, by regulating the admission of fresh air, any degree of heat may be attained. We are well aware of the prejudice,- almost 142 WARMING OF BUILDINGS, universally existing in Great Britain, in favour of open fireplaces, and we must confess to our ap- proval of its avowedly cheerful and comfortable (according to the English sense of the term) appearance ; but we cannot, at the same time, be blind to its great faults, the chief of which is its unequal heating powers. Foreigners justly com- plain that, in our apartments, " one side is starved, the other roasted." Now this might easily be obviated by combining heating by pipes and by the open fireplace retaining the cheerful blaze of the one, warming by radiation, and having also the efficient heating of the other, by pipes warming chiefly by contact. This plan of combination has advantages too obvious to be mentioned here one, decidedly of great importance, being the doing away with the necessity of a large scorching fire, which, as our old author, already quoted, quaintly observes, " dries up the lungs and ruins the eyes, as may be perceived by their pain and redness; spoils the delicate skin of the ladies, hurts the eye- lids, and destroys the finest complexions." We are aware that, in recommending the adop- tion of the more scientific plans we have mentioned, to secure healthy and equable warmth in our apart- ments, we have to struggle against the prejudices of the great majority of people, as to what they are pleased to term " new-fangled notions." But we are convinced that, if our plans and suggestions are adopt- CONSTRUCTION OF FIREPLACES, ETC. 143 ed in any one case, the advantages will be so strik- ing and satisfactory, that their adoption will be con- sidered by many. No improvements, in any de- partment of science, have ever yet been introduced without difficulty and opposition ; but by degrees public attention has been directed to them, and their adoption gradually become general. And so it has been with the important improvements we have noticed and commented upon ; several of them have been promulgated years ago, yet it is only very recently that they have been adopted : we are content, in the mean time, to add our quota to the amount of information diffused, trusting that our prac- tical hints will be found somewhat useful, in proving how easily they can be carried into effect. As to these "new-fangled notions" of the present day, what will the disciples of the " stand-still " school say to the following exposition of a plan, promulgated by our old author so many years ago, by which the useful effect of heated air is carried to an extreme that even our most enthusiastic ventilators would never dream of and yet there is positively no- thing absurd in the idea it could be efficiently and usefully carried into effect : " If any one would have the warm air that comes into the room (by the plan we have already explained) to fall with all its heat on their hands or feet, to warm them in a little time, and keep them warm at any distance from the fire, they may easily do it, by setting one 144 WARMING OF BUILDINGS, end of a tin or pasteboard pipe at the upper hole, where the warm air comes in, and the other end near the part which they would warm. Such a pipe may be carried into a bed, and warm it to any degree, by discharging its heated air into it ; and as such a tube takes up but little room, the bed may be warmed whilst anybody is in it ; and the warm air may be thrown upon any part of the body, so as to warm it as long as you please which will be of great use, especially in some dis- tempers, where it is required to apply warm napkins constantly to a patient. Those that can get no heat in bed, in hard winters, may be thus warmed." We would here particularly warn churchwar- dens, and proprietors of public buildings, against the dangerous practice of heating by means of hot- air cockles, high-temperature stoves, &c. We do not know of a single instance where a church has been burned, but the cause could be traced to an old-fashioned defective stove. Let those using such consider, that heated air projected against any combustible, predisposes it to catch fire easily ; and if the air is heated to a great degree, the com- bustible will be charred, and most assuredly set fire to. Let it be remembered that lead may be melted instantaneously by being subjected to the current of warm air produced in a cockle exactly similar to those used too frequently in many CONSTRUCTION OF FIREPLACES, ETC. 145 churches, &c. that wood, nay, coals, can be almost instantly ignited by similar currents and it will be perceived that the danger of such contrivances is very great: that, in truth, each time the build- ing is heated by such, the risk is run of setting the place on fire, more especially if the heated air be supplied by pipes running near to, or in contact with, wood work. We have only, in corroboration of our remarks, to point to the burning of the Greyfriars' church in Edinburgh, and that of All- Saints in Manchester, both of which originated in the heated air from the stoves igniting the wood work. We are aware that the expense of fitting up hot-water pipes is greater than for common stoves, but surely the common rules of prudence and worldly wisdom will convince the proprietors of public buildings, that there is no saving in fitting up contrivances which may set fire to the structures in which they are placed, each time they are used. By a properly constructed " low-temperature " hot- water apparatus, it is a perfect impossibility to heat any combustible to ignition. Construction of Fireplaces. Without stopping to enter into an inquiry as to the antiquity of chimneys, or when they were first used, interesting as such would undoubtedly be, we will at once proceed to give practical hints for their improve- ment. We will first consider the position of the grate mode of forming the covings or sides and 146 WARMING OF BUILDINGS, height and diameter of chimney flue. The object, in all ordinary grates, is to heat the floor : " if this be accomplished, it moderates the severity of the cold air there, and the upper portion of the apart- ment is warmed by the ascending currents that are immediately developed." The bars should be made as light as possible, as it is evident, the heat being radiated from the burning surface, heavy bars, covering a large portion, must prevent it. It is only when substances are red-hot that they shed out much radiant heat the importance will be seen, then, of having the fuel burning as clear as possible. To insure this, the fire should be sur- rounded, on three sides, by slow conductors of heat. The plan, too often carried into effect, of having the whole body of the grate made of iron, is very erroneous in principle, as it is evident that so much of the heat will be withdrawn, that the fuel will burn dull and dead. Fire-brick is now becoming more generally used to surround the place where the fuel rests : it would be well if all manufacturers of grates would be convinced of the advantages to be derived from such a plan. The more surface of burning fuel obtained, the more heat will be sent into the room : to effect this, and at the same time to obviate the necessity of having a large and ex- pensive body of fuel, the back of the grate should be provided with a projection in the centre, coming forward into the body of the fire, till within nearly CONSTRUCTION OF FIREPLACES, ETC. 147 three inches of the front bars this should be larger at the base, where it joins the back, than at the front. It may be made of fire-brick, and should be firmly- built in with the rest of the back. This is highly- recommended by Mr Tredgold. As to the pro- portions for the front of the grate, Mr Tredgold says, that " if the length of the front of the grate be made one inch for each foot in length of the room, and the depth of the front be half an inch for each foot in breadth of the room, the propor- tions will be found tolerably near the truth, in the cases usually occurring in practice." In the construction of fireplaces, the mode of forming the covings is of the utmost importance ; And here let us stop to examine under what form the heat generated in the combustion of the fuel exists, and how it is communicated to those bodies which are heated by it. We have in some measure considered this, but as it will enable the practical man to perceive the advantages of the suggestions we will hereafter give, we deem it necessary here more fully to enter into it ; and, in doing so, we cannot do better than give the following extract from Count Rumford's treatise : " It is quite certain that the heat which is generated in the combustion of the fuel, exists under two perfectly distinct and very different forms. One part of it is combined with the smoke, vapour, and heated air which rise from the burning fuel, and goes off with 148 WARMING OF BUILDINGS, them into the upper regions of the atmosphere ; while the other part, which appears to be uncom- bined, ... is sent off from the fire in rays in all possible directions. . . . It is highly pro- bable that the combined heat can only be commu- nicated by actual contact with the body with which it is combined ; and, with regard to the rays which are sent off by burning fuel, it is certain that they communicate or generate heat only when and where, they are stopped and absorbed. In passing through air which is transparent, they certainly do not communicate any heat to it ; and it seems highly probable that they do not communicate heat to solid bodies by which they are reflected. . . . A question which naturally presents itself here, is what proportion does the radiant heat bear to the combined heat? Though that point has not yet been determined with any considerable degree of precision, it is however quite certain, that the quantity of heat which goes off combined with the smoke, vapour, and heated air, is much more con- siderable perhaps three or four times greater, at least than that which is sent off from the fire in rays. And yet, small as the quantity is of this radiant heat, it is the only part of the heat, gene- rated in the combustion of fuel burnt in an open fireplace, which is ever employed in heating a room." It becomes, then, of " much importance to determine how the greatest quantity of it may be CONSTRUCTION OF FIKEPLACES, ETC. 149 generated in the combustion of the fuel, and how the greatest proportion possible of that generated may be brought into the room" We have previously shown that, when the fuel burns clearest, the most radiant heat is sent into the room ; and also that, by a greater surface of red-hot fuel, the same effect will be obtained. It will be seen then, in reference to this point, that the common practice of heaping on coals, and smothering up the fire, is the very way to render the combustion of the fuel least effective in heating the room. On this point Count Rumford remarks, " Nothing 'can be more per- fectly void of common sense, and wasteful and slovenly at the same time, than the manner in which chimney fires . . . are commonly managed by servants. They throw on a load of coals at once, through which the flame is hours in making its way ; and frequently it is not without much trouble that the fire is prevented from going out. As the rays," continues our author, " which are thrown off from burning fuel have this property, in com- mon with light, that they generate only wlien and where, they are stopped or absorbed, and also in being capable of being reflected, without generat- ing heat, at the surfaces of various bodies, the know- ledge of these properties will enable us to take measures, with the utmost certainty, for producing the effect required that is to say, for bringing as much radiant heat as possible into the room." To 150 WARMING OF BUILDINGS, insure this being effectually done, the sides or covings should be made so that the rays will be reflected into the room. Guager, in his Fires Improved, published in France in 1713, (translated by the celebrated Dr Desaguliers, and published in London in 1716,) and from which we have already quoted, was the first to demonstrate, that fire- places with sides perpendicular, or at right angles to the back, were very ill calculated to throw the rays of heat into the room ; and he clearly proved that the parabolic curve was best adapted for the purpose. This, however, is difficult for most work- men to describe : and Count Rumford proved that the fireplaces with the sides forming an angle of 135 with the back, threw the heat effectually into the room. This is a form easily made, and he describes it as follows, " The best form for the vertical sides of a fireplace, or the coverings, (cov- ings,) as they are called, is that of an upright plane, making an angle with the plane of the back of the fireplace of about 135. To have a clear and per- fect idea of the alterations, ... the reader need only observe that, whereas the backs of fire- places, as they are now commonly constructed, are as wide as the opening of the fireplace in front and the sides of it are of course perpendicular to it, and parallel to each other in the fireplaces I recom- mend, the back is only about one-third of the width of the opening of the fireplace in front, and, con- CONSTRUCTION OF FIREPLACES, ETC. 151 sequently, the two sides or coverings of the fire- place, instead of being perpendicular to the back, are inclined to it at an angle of about 135. " Tredgold recommends the covings to form an angle of 45 with the line of the front bars of the grate ; but, to insure the full effect of these reflect- ing surfaces, they must be made capable of reflect- ing the chief part of the heat which they receive. We have shown, in the first part of this Chapter, that " polished metals are bad absorbers of radiant heat, but powerful reflectors, throwing back a large portion of any radiant heat that falls upon them." The covings should be made, then, of plates of polished metal, to insure the full effect of the angular surfaces : these are, however, difficult to be kept clean and bright ; other materials may be substituted. The best we can recommend is highly glazed earthenware, of a cream-coloured hue, as white is not very agreeable to the eyes ; or a light blue or delicate green : the nearer, how- ever, it approaches to white, it will be better. Backs and sides of grates might be made highly ornamental, by the adoption of elegant designs in this material. For cheap reflectors, the covings should be smoothly plastered, and painted white never, in any instance, allowing them to be painted black. Though this is the colour generally seen, it is the very worst possible to be used. The next thing to be considered is the construction of chimneys. 152 WARMING OP BUILDINGS, " Chimneys," says Dr Arnott, " quicken the ascent of hot air, by keeping a large quantity of it together. A column of 2 feet high rises with twice as much force as a column of 1 foot, and so on in proportion for all other lengths In a chimney, 1 foot in height of the column of hot air, may be 1 ounce lighter than the same bulk of the external cold air ; and if the chimney be 100 feet high, the air or smoke in it is propelled upwards with a force of 100 ounces. In all cases, therefore, the draught, as it is called, of a chimney is proportioned to its length." As slow combustion is more favourable for throwing off radiant heat, the draught of the chimney should not be so great as to make the combustion rapid, neither should it be so feeble as to keep a dull fire, and be easily forced down by adverse currents. Very little attention has been paid to the proper construction of chimney flues : they are generally made at hap- hazard, and bear no proportion to the size of grate they have to draw the smoke from. Mr Tredgold gives, from deductions made by him, the following rule, which gives the area of size at top, which should be increased a very little at the bottom, near the fireplace. " Let seventeen times the length of the grate, in inches, be divided by the square root of the height of the chimney in feet, and the quotient is the area for the aperture at the top of the chimney in inches." All chimney-flues, in CONSTRUCTION OF FIEEPLACES, ETC. 153 newly-constructed buildings, should be made cir- cular : the advantages of such a mode are so obvious that they need not here be commented upon. Earthenware tubes are now made of all diameters, and are admirably adapted for the inside of chimney-flues. Those made by Doulton of St Helen's, Lancashire, for drainage purposes, would do admirably. We have stated above that the mouth of the chimney-flue should be of a little larger diameter than that of the top, but if made of the same size it will be sufficient. There should, if possible, be no bending^ in its course : if these are necessary, from local circumstances, they should invariably be made with easy curves. The earthenware tubes referred to can be had with curves of every radius used. The openings of the flue should be made right above the mass of burn- ing fuel, that the ascent of heated air and smoke may be in a perpendicular direction. A writer on the subject recommends the sides and back of the grate, after a certain perpendicular height, to slope or bend " inwards, from all points, immediately on reaching the height of the lower edge of the man- tel, only so as to avoid acute corners, so that the insertion of the vent into it at the throat may resemble the insertion of the tube of a funnel into its mouth, or that of a stove-pipe into its fireplace." This is an admirable idea ; but, in carrying it out, care should be taken, if the bent parts are made of 154 WARMING OF BUILDINGS, iron, to cover them on the wrong side with a thick coat of plaster, to prevent the loss of heat by conduction ; and that the inside, above the fire, be polished, or at least whitened, to reflect the rays of heat from its surface. The same writer who gives this plan also recommends the circular chimneys, but, unfortunately, he advises them to be made with the diameter gradually increasing towards the top. The reason he gives for this recommendation is, that, as the heated air and smoke rises in the chimney, there will be a proportionate decrease of temperature, " and, consequently, a sort of accumu- lation and thickening of the smoke will take place in the upper end of the vent at least, where it does not widen gradually, there will be such a tendency, though the effect may be prevented by the vent being in every other respect properly constructed. But if such a chimney be disadvan- tageously situated, where the wind bears down into it from causes hereafter to be noticed, it will give way to the wind, and the smoke will be forced down into the room, which would not take place were the vent constructed on the principle of gradual expansion. By this principle, the tendency of the smoke to accumulate will be relieved by the column finding more room as it advances, in pro- portion as it falls off in velocity." The statement made by this writer, that the heated air falls off in velocity as it ascends the chimney, is perfectly CONSTRUCTION OF FIREPLACES, ETC. 155 correct; but he seems to have forgot that the philosophical way of increasing the velocity was by diminishing the aperture just as we find that, when a river is confined within narrow banks, it runs with great velocity, while the same water, spread over a wide surface, is scarcely seen to move at all. The proportion for the height of the opening of a fireplace that is, from the hearth to the foot of the mantel-tree seems to be one-third of the height of the floor from the ceiling. This may appear inelegant, but the above writer says he has found it, in his practice, to be a safe pro- portion. We have given in a former part of this Chapter a description of a grate, by which the effects of combined heat may be made useful ; care should be taken to have the canals completely closed from all communication with the chimney flue. (See page 140.) In constructing chimney fireplaces, the greatest care should be taken to prevent wood-work having contact with any parts of the construction ; impor- tant as this is, we regret to say that no great degree of attention is ever paid to it. The utmost carelessness is displayed in the filling up of the back parts of grates shavings, pieces of wood, are often found to be promiscuously shoved in. Every part should be tightly cemented, or at least well plas- tered, so that there can be no lodgment of soot in 156 WARMING OF BUILDINGS, any part. We feel convinced that nine out of every ten cases of fire originate in, or about the fire-places the fire communicating, in some one of the numerous ways too often left for it, with the combustible materials around the grate or chimney. Care should be taken in cleaning chimneys the heavy Lumbering contrivances should never be adopted ; we think we are warranted in saying that the broom and rope used in Scotland will be found as effectual as any other. "Were proprietors of houses," says a writer, " intended to be let, to place fixture grates in them at first, when they would be set, free of any of these combustible materials, and more substantial ; much risk would be avoided ; besides the destruc- tion of paper, paint, and plaster occasioned by tearing out of grates, and putting in others of different construction. While an annual source of destruction and danger to the landlord's property would thus be done away with, a large yearly expense would be saved to the tenant, who would live in greater security from danger by fire." These remarks are more applicable to the condition of matters in Scotland, the tenants having in nearly all cases to supply themselves with grates. On this very important point we cannot refrain from giving the following long extract, from a work by Mr Beaumont of London, entitled, Hints on preventing Damage ly Fire, convinced that our CONSTRUCTION' OF FIREPLACES, ETC. 157 readers will derive considerable benefit from its perusal : " One of the most fruitful sources of accidents in common buildings in the country is a beam of wood for the chimney breast: this ought always to be of iron. . . . Then, as if courting conflagration, timbers are laid close to flues, and sometimes even within the flue itself. . . Trim- mers, joists, rafters, and girders protruded through the sides of flues, and even when lodged against the sides of flues, occasion numerous accidents. . . . The danger from fire, and the instability of brick-work are greatly increased by a practice, among scamping workmen, of leaving hollow places called pockets in their walls, and in using only so much mortar,' in laying their bricks, as give a fair joint to the eye, leaving all behind hollow. The hollows get filled with soot ; and when a fire takes place in an adjoining flue, the sooty chinks form a train which sets the building on fire. , t A minor cause of alarm sometimes arises from the setting of block chimney-pieces in such a manner as to have a communication between the hollow of the chimney-piece and the flue, in which hollow the soot gathers, and at length takes fire ; but a more frequent cause, of the same kind, consists in the grate being set hollow behind. In this receptacle the soot falls and collects for a length of time, until it reaches the middle of the grate, when, upon the back becoming red-hot, it lights the heap, and pro- 158 WARMING OF BUILDINGS, duces such an intense fire as to endanger the adjacent wood-work. . . Firing from altera- tions in flues, and additional flues erected in old buildings, are very common. The workmen must be, of necessity, somewhat in the dark as to the precise layings of adjacent timbers ; but the indif- ference with which they disregard the contiguity of timber, which they see or know off, is frequently remarkable. . . . Iron stoves set on a wood floor, and having iron pipes, are always more or less dangerous. It is thought enough to have a sheet-iron fender to set the stove upon, but more is necessary to be secure. Iron pipes to these stoves are full of danger ; when they are not in use, par- ticularly if there be much soot left in them, they col- lect moisture and are rapidly oxidised. Then, when they become filled with soot, and the soot takes fire, it burns fiercely ; and the fire drops through the rust holes and the joints, and if these drop- pings occur between a wainscoting, or a battening, and a wall, at the hole where the pipe enters the brick flue, it is likely to set the house on fire. The danger is more imminent if the pipe passes through a floor, or lath and plaster partition." Smoky Chimneys. A smoky chimney has been well characterised as one of the most annoying of our house discomforts. Annoying as it undoubtedly is, it is matter of astonishment that, with one or too solitary exceptions, no really successful remedy has CONSTRUCTION OF FIREPLACES, ETC. 1 59 ever been applied to overcome it. However, our surprise may be considerably lessened, when we consider that the generality of individuals who have directed their attention to the subject, have been utterly ignorant of the philosophical laws which regulate the movement of heated air. Ne- glecting, or entirely overlooking the study of these, they have depended upon various plans and machines for effecting a cure, the most of which have been constructed in complete defiance of all natural laws. It certainly is matter of regret, that scientific men should have so long considered this subject beneath their notice. We free them from the imputation of inability to cope with its difficulties, but we blame them for their indiffer- ence ; more especially as, by turning their attention to the subject, they would not have compromised their professional dignity, which, we suspect, they were afraid of doing. Of late years, however, we have seen engineers and scientific menj high in their respective professions, who have not thought it unworthy of their special attention. This has resulted, fortunately, in making known very many valuable suggestions^ scattered here and there, through the records of their experience and experiments : these, in the course of our own remarks, we intend to present to the reader, nothing doubting but that he will derive much information, of high practical value, therefrom. 160 WARMING OF BUILDINGS, " In the Vespse,' 1 says Beckmann, in his History of Discoveries, " of Aristophanes, old Philocleon wishes to escape through the chimney. Some one asks, l What is that which makes such a noise in the chimney?' ' I am the smoke,' says the old man, ' and am endeavouring to get out at the chimneys'" If the smoke in the chimneys of our day were thus gifted with the power of speech, how many would tell the same tale ? very probably, nine out of ten are so badly constructed that it really al- ways is an endeavour, on the part of the smoke, to escape from them. Now, as the natural course of heat- ed air is upwards, there must be something very materially wrong in the construction of chimneys, when the smoke is prevented from easily ascend- ing. The idea that generally obtains, that smoke is really lighter than air, is very erroneous ; in reality, it is the converse : " it consists, 1 ' says Dr Arnott, " of all the dust and visible particles of the fuel, without being burned, and are, moreover, light and minute enough to be carried aloft by the rising current of heated air ; but all that is visible of smoke is really heavier than air, and soon falls again, as powdered chalk in water. In the receiver of an air-pump, where a candle has been extin- guished by exhausting the air, the stream of smoke that continues to pour from the wick, after the exhausting, is seen to fall on the pump-plate, because there is no air to support it. A familiar CONSTRUCTION OF FIREPLACES, ETC. 161 illustration of this truth, may be seen in close days, when the smoke hardly ascends, when the air, within the very zone of respiration, is full of smoke, surcharged with smutty particles. The air is so rare and light, that it cannot support the heavy particles of the smoke they consequently fall to the ground ; hence may be seen the absurdity of the popular opinion, that the air on these occasions is so heavy, while, in fact, it is the very reverse. It will thus be seen, how the visible part of smoke ascends merely as it is mixed with the heated air, the products of combustion, of which it forms a part. If the reader has sufficiently attended to our remarks, at the commencement of this treatise, he will understand how the heated air is pushed upwards by the colder and denser air, at the bottom ; and that, unless a supply of cold or dense air is kept up below, no upward current can possibly take place. Now we humbly conceive that, in the proper application of this natural law, lies the key to the solution of the difficulty of curing smoky, chimneys. That the reader may fully understand what we mean, we here put it specifically, Heated air cannot ascend a flue, or chimney, with force sufficient to overcome opposing currents, unless a due supply of fresh and denser a'r is suppli.d below, at or near to the fireplace. Now the result of all experience goes to prove the axiomatic truth of i, 162 WARMING OF BUILDINGS, this, independent of its theoretical accuracy. In every work we have studied and to almost every one worthy of notice have we referred this is stated as a decided principle ; and our own experience has invariably given satisfactory proof of its accuracy. Guager, in his work, (1713,) gives a plan for supplying fresh air near to the fire- place, exactly similar to the one we have seen adopted with much success, before ever we heard of his book : it consists of an aperture in the hearthstone, connected with a ventiduct, or air channel, leading to the external atmosphere Dr Franklin says, " Smoky chimneys in a new house are such, frequently, from mere want of air." Silver, in his treatise on smoky chimneys, says that the two points, on the knowledge of which the adopting of proper remedies for smoky chimneys will materially depend, are, " First, that a constant and proportionate supply of cold air, is necessary to supply the place of the heated air, continually passing up the vent; and, second, that it is from the lower part of the apartment the supply will (ought to) be chiefly derived. Dr Arnott says, " Perhaps the best method of admitting air, to feed the fires, is through tubes leading directly from the outer air to the fireplace." And Dr Eeid says, " Nothing is so common a cause of smoke, as an insufficiency in the amount of air supplied to any apartment. CONSTRUCTION OF FIREPLACES, ETC. 163 By having the flues and fireplaces constructed according to the rules and suggestions we pre- viously explained, by supplying a due amount of fresh air to the fireplace below, no chimney will smoke. On the other hand, we do not hesitate to say, that, however well arranged and constructed the flues and fireplaces are, if not supplied with a proper amount of air, they will inevitably smoke. So unvarying in its action is the law we have noticed, in its operation, that, whenever a chimney smokes, we may rest assured that the supply of air below is deficient that some opposing current has overpowered the ascending smoke and heated air. We do not remember of ever seeing a case in which the opening of a door or window did not restore the natural current, and cure the smoke. Had the course of the air admitted by the door or window been traced, it would, in every case, with- out exception, have been found making directly to the fireplace. Many rooms smoke, on account of the air therein being drawn away to supply a larger fire in another apartment, not properly sup- plied with air. Were the two rooms supplied, inde- pendently of each other, with a sufficiency of air, the chimneys in both rooms would draw well, without smoking. We know of one instance in which almost all the chimneys in one house smoked ; the course of the current was examined, and it was found that a large stove in the laundry actually 164 WARMING OF BUILDINGS, drew its supply of air from the fires below, through the medium of the staircase. The laundry, situated above, after this, being well supplied with air, the other chimneys ordinarily drew well. Large kitchen fires frequently draw their supply from other apartments, causing these to smoke, if fires are lighted in them. A fire which has been in operation all day in a sitting-room, in the same floor with a drawing-room, has overpowered the newly kindled fire in the latter ; by drawing the air therefrom for its own supply, the newly assem- bled visitors have been obliged to vacate the apart- ment. A person at all acquainted with the subject w,ould have at once discovered the cause, and, by the opening of a window in the sitting-room, through which a supply of air could have been obtained, independent of the drawing-room, the difficulty would at once have been obviated. In this case, the sitting-room, when its windows were shut, habitually drew its supply from the drawing- room. A large drawing-room, with all the appli- ances to insure what is deemed comfort namely, tight-fitting doors and felted windows was heated by two fireplaces, one at each end of the apart- ment. One grate was larger than the other ; when in full action, it drew its supply of air from the flue of the small fireplace the smoke, of course, descending to the room ; when the fire in the small grate was in full force, and that in the large feeble, CONSTRUCTION OF FIHEPLACES, ETC. 165 the action above explained was reversed. This amusing but disagreeable state of affairs could have been at once obviated, by giving each a supply of fresh air. We could cite numerous examples of the truth of the principle we have enunciated, but we do not consider it at all necessary. Having drawn general attention to the fact, we doubt not that all observations hereafter made will corrobo- rate its truth. The course of the current in a smoky room must be found, in applying the principle to cure it. This will best be done by a small lighted taper, or a small piece of smouldering brown paper, emitting smoke. By holding this quietly in the room, the direction the flame or vapour takes is that of the current of air ; if it leads to a stronger fire in an- other apartment, rest assured this derives its supply from the room smoking. Supply the room with the strong fireplace with air. To every room in a house would we recommend the following plan to be car- ried into effect, whether such rooms be smoky or not whether they smoke by supplying fires in other apartments, or by opposing currents, caused by winds forced down the chimney. From the open air lead a pipe, varying in size according to the size of room or grate, (not less than two inches for a bed- room grate,) from a hole made in the wall to the space beneath the hearthstone, immediately below the place where the fender usually stands ; let an 166 WARMING OF BUILDINGS, orifice be made in the hearthstone, above the termi- nation of the fresh air pipe covered, if so wished, with a small iron grating; let a few apertures, equal in area to that of the aperture, be made in the fender, above the aperture or louvre-shaped open- ings may be substituted in place of the holes, to prevent dust and ashes going into the air aperture in the hearthstone. The ventiduct thus made should in all cases be supplied with a valve to regulate the admission of the air. The ventilating grate, recommended by William Hosking, Esq., previously mentioned, may be used with advan- tage, instead of the plan we have here given ours is much more simple, and will be more easily car- ried into effect. Better err in making the supply of air too large than too small ; the fire will take no more air than it actually requires. The air channel thus recommended, serves another important purpose, which must not be omitted to be noticed here " it leaves the apart- ment free from many of those draughts and cur- rents that are common to all ordinary rooms with fires, and which pass in general between the win- dow and the fireplace, or the door and the fire- place." In some instances the air is supplied at the back of the grate, beneath the bars; but we approve of the plan of having the aperture at the front, so that the air will be thrown upwards, where most required, without meeting with opposing surfaces. CONSTRUCTION OF FIREPLACES, ETC. 167 Chimneys, when made very wide at their orifices, or throughout the length of the flue, are predis- posed to smoke. In such cases the heated air is often found to be ascending by one side, while the fresh air is actually coming down the other to supply the fire consequently, the ascending column of heated air being considerably cooled, any opposing current has a great effect in relaxing it. Hence, such chim- neys frequently smoke in high winds. It is evident that, by adopting the plan we have proposed, there will be no necessity for a downward current of air through the chimney, sufficiency of air being sup- plied below. But, in all cases, the apertures for the egress of the smoke should not be larger than is absolutely required. We have before given a rule to find the size in newly constructed chimneys it is applicable in cases where the degree of con- traction is required to be found for wide chimneys already made. A practice obtains amongst many practitioners, of contracting the orifice of the chimney at the bottom, nearest the fireplace. " It is like, " says Tredgold, " contracting the aperture which supplies a jet." This is a much disputed point, almost all practitioners contracting the orifice at the bottom. Clauvelin and Gilbert have, how- ever, demonstrated the advantage of contracting at the top. We have already noticed one good effect of this mode namely, increasing the velocity of the heated air just at the place where, from its 168 WARMING OF BUILDINGS, decreased temperature, it is most required. It is best to have the flue of the chimney of equal dimensions throughout, the bottom being a little larger than the top, if conveniently made this way. It is undoubtedly a good plan to contract a wide chimney near the fireplace, even were it for nothing else than the prevention of eddies and currents, which would otherwise be created; but it will, moreover, by increasing the velocity of the current, be of material advantage in assisting the upward current. But, in all cases, the top should also be contracted. After finding the area of the proper aperture, after contraction, by the rule previously given, (see page 152,) the following plan should be adopt- ed a a the chimney-pot, b b the iron part for contracting. The bottom part should be rounded as at d d, the parts c c should be made angular, as shown the angular faces very much facilitating the passing of the wind over them. The parts b b may be made of Ro- man cement with advantage, as the heat of the smoke will not be conducted, as would be the case with the iron ; or, if made of iron, their interstices might be filled up with non- conducting material. CONSTEUCTION OF FIREPLACES, ETC. 169 Some chimneys draw "well in calm weather, and in certain high winds ; but with some particular Avind, whether strong or moderate, they smoke very badly, in proportion to the strength of the breeze. As the smoke in these cases is occasioned by the wind either striking on some adjacent building or eminence, or from some local peculiarity of the orifice of the chimney, it is necessary to pro- vide " tops " on the outside, to prevent the down- draughts which are thus occasioned these being in some cases so strong as to overpower even the best regulated currents of heated air in the chimney flue. The tops used in such cases are so designed that the apertures for the escape of the smoke are either always turned away from the wind, (by the force of the wind itself,) as in the common revolving ventilator or cowl; or the apertures are arranged and commanded by well-designed covers, so that it is impossible for the wind to blow down in any case. We would in all cases recommend fixed and per- manent tops, instead of the movable caps or cowls, so generally used : they do not make any disagree- able noise, and last much longer. The top figured in Chapter II. may be adopted with success. As a really efficient cap, we can cordially recommend Kite's (of London) diamond-deflecting chimney- top : it is constructed on truly philosophical prin- ciples; and in every case where adopted, (the other parts of the chimney being properly constructed, 170 WARMING OF BUILDINGS, and a good supply of air secured below,) it has given great satisfaction. It has been adopted by the honourable the Commissioners of Woods and Forests. As a top which cannot fail to be effectual, and down the chimneys on which it is placed the wind cannot possibly go, we give the following, taken from Guager's work pre- Fig- 1. viously alluded to. Fig 1. is a side elevation ; cut out of a sheet of thin plate-iron a piece shaped as in the figure. The dimensions will vary, according to the size of the chimney ledge and orifice. The follow- ing will be found to be good proportions : If the base A a is 14 inches broad, let a & be 8 inches, b c 6 inches, and e d also 6 inches ; the breadth c g, d g 1 , 12 inches or 11 would be better, as more slope would thus o"e given to the part c b] d e 8 inches, and e /equal to the aperture of the mouth of the chimney, as found by the rule previously given. The common clay chimney can or top, as shown by the dotted lines, is placed on the aperture of the chimney. At the height, and on a line with d cj, draw the base of a triangle r s, 2 inches longer than the mouth t of the top ; make the sides r f, st, of length sufficient to make the apex t be in a line CONSTRUCTION OF FIEEPLACES, ETC. 171 with the aperture of the chimney-top : cut this out with a chisel, thus making a triangular opening. Having thus got one side, make another exactly similar, by laying this on a sheet of iron and tracing all round the edges, and thereafter cutting it out. Supposing the square of the chimney on which this top is to stand to be 14 inches, then these two ends are to be joined together by sides 14 inches long, on the parts e d, d c, c &, leaving the part a' b open. When the top is thus far completed, make a triangular prism of iron, or plate-iron, with the three sides firmly and neatly fastened together ; this should be less than the hole r s t, cut in the ends, and 14 \ inches long. Shove this through the apertures r s t, so that each Fi s> 2 end of the prism will rest upon the edges of the holes in the ends. The arrows will show how easily the smoke will gain egress ; and how difficult it will be for the wind, even if blowing directly down, to enter the aperture of the chimney in- deed, when the chimney is in action, it will almost amount to an impossibility. Fig. 2 is a side view ; B the open part, left uncovered on each side. (The same let- ters refer to both figures.) Where the chimney only smokes in certain high 172 WARMING OF BUILDINGS. winds, by what is called a blow-down, a well-con- structed top, such as we have now described, will in some measure cure it 5 but all such contrivances will, in the generality of cases, be totally ineffectual, without a proper supply of fresh air is admitted to the fireplace below. We would, then, strongly recommend, in all attempts at curing smoky chim- neys, to make this the first essential ; and while doubtless improving the other parts, in accordance with our suggestions, to make such subordinate to, and as supporters of, the first great principle. We are decidedly of opinion that no chimney, however well constructed and provided with all appliances, will draw well, at all times, and under all circum- stances, unless a due supply of fresh air is provided below ; and that, for economy and certainty of success, the best mode of supplying that air is by leading it, in pipes or conduits, from the open air at once to the fireplace, so as to be independent of all other sources, even of air supplied to the apartments by well-devised and efficient ventilating contrivances. RECAPITULATORY REMARKS IN ventilating public buildings, it should be borne in mind, that half-measures will not give satisfaction. Foul-air ventiducts, without provision being made for admission of fresh air, and vice versa, will be totally ineffectual in ventilating the building efficiently. To obtain the full advantage of the plans we have explained, it is absolutely necessary to have the fresh and foul air ventiducts acting in concert not independent of one another. If the air at the bottom of the walls is impure, or liable to be mixed with dust, or other ex- traneous matter, the fresh -air ventiducts should be made in the interior of the walls, as shown in page 26. All fresh-air apertures, wherever made, should have their external mouths guarded with bars or large perforated zinc, (see p. 48,) and should be furnished with valves, to regulate the admission of the air, (see p. 28, 29.) The foul-air ventiducts should be fixed at the 174 RECAPITULATORY REMARKS. highest part of the ceiling, (see p. 32,) and be provided with valves, (see p. 35, 36.) If the ventiduct should be of the second construction, (as shown in p. 36,) an ornamented board should be fixed beneath it, as there recommended. The ventiducts should be extended above the ridge of the roof, and properly finished at top, (see p. 41.) The galleries should be provided with separate fresh-air and foul-air ventiducts, (see p. 38.) In theatres, hospitals, &c., where large foul-air ventiducts cannot be used in the central roof, it will be necessary to provide air channels in the side or end walls. These may be made similar to the plan described in page 26 the aperture for the admission of the foul air being, of course, in the interior of the building, and as near the ceiling as possible ; the aperture for its egress, made as described in pages 47, 48. In ventilating private apartments, it is essential to have apertures for the ingress of fresh, and the egress of foul air, acting in concert. For the modes of admitting fresh air, see pages 64 to 68. In whatever way the fresh air is admitted, care must be taken to diffuse it before entering the apartment, (see p. 64 67.) For withdrawing the foul air, any of the modes proposed in Chapter III. may be adopted. One objection may be made to the tube described in page 73 namely, that, by projecting so far into the interior of the flue, it EECAPITULATORY REMAKKS. 175 may be in the way when the chimney is being cleaned. This, however, may be obviated by putting the " cap " near the wall. The following are other plans : Let an aperture be made in the wall above the fireplace, near the ceiling, leading to the chimney. From this aperture a pipe may be led up the interior of the flue, close to the wall, and extended some twelve or eighteen inches above the external opening, or aperture of the chimney-can ; and provided with a cap or top, to prevent the smoke being blown down. This contrivance will be thoroughly effectual. It bears a close resemblance to the syphon principle, yet is some- what different : it will act best when there is a fire in the room. The annexed figures are expla- natory of a room-ventilator, the invention of Mr William Bryden, of George Street, Edinburgh. In cases where the fireplace is well supplied with air, in the manner we have previously described, a more elegant, simple, and thoroughly efficient con- trivance could not be adopted for the ventilation of private apartments. It is decidedly by far the best we have yet seen or examined. Of course, in fit- ting them up, every care should be taken to pre- vent blow-downs in the chimneys to which they are A hole b is cut in the wall near the ceiling, communicating with the chimney ff. Into this is inserted a tin or iron funnel, shaped as seen in the 17G RECAPITULATORY REMARKS. figure. At the large diameter of the ventilator, hi the interior of the room, a lid or covering is placed, hinged at one side, as at